[cfe] Make extension type non-nullable only if it implements Object

Part of https://github.com/dart-lang/sdk/issues/49731

TEST=existing

Change-Id: I397bbd5ca7868a9fb344286c910536c6ac341222
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/333500
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Srujan Gaddam <srujzs@google.com>
Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>

pkg/front_end/lib/src/fasta/builder/extension_type_declaration_builder.dart

@@ -68,7 +68,6 @@ abstract class ExtensionTypeDeclarationBuilderImpl
       Uri fileUri,
       int charOffset,
       {required bool hasExplicitTypeArguments}) {
-    buildRepresentationTypeAndName();
     ExtensionType type =
         new ExtensionType(extensionTypeDeclaration, nullability, arguments);
     if (typeVariablesCount != 0 && library is SourceLibraryBuilder) {
@@ -80,6 +79,4 @@ abstract class ExtensionTypeDeclarationBuilderImpl
 
   @override
   String get debugName => "ExtensionTypeDeclarationBuilder";
-
-  void buildRepresentationTypeAndName() {}
 }

pkg/front_end/lib/src/fasta/source/source_extension_type_declaration_builder.dart

@@ -47,7 +47,6 @@ class SourceExtensionTypeDeclarationBuilder
   final List<ConstructorReferenceBuilder>? constructorReferences;
 
   final ExtensionTypeDeclaration _extensionTypeDeclaration;
-  bool _builtRepresentationTypeAndName = false;
 
   SourceExtensionTypeDeclarationBuilder? _origin;
   SourceExtensionTypeDeclarationBuilder? patchForTesting;
@@ -255,19 +254,6 @@ class SourceExtensionTypeDeclarationBuilder
       }
     }
 
-    buildRepresentationTypeAndName();
-    buildInternal(coreLibrary, addMembersToLibrary: addMembersToLibrary);
-
-    return _extensionTypeDeclaration;
-  }
-
-  @override
-  void buildRepresentationTypeAndName() {
-    // We cut the potential infinite recursion here. The cyclic dependencies
-    // should be reported elsewhere.
-    if (_builtRepresentationTypeAndName) return;
-    _builtRepresentationTypeAndName = true;
-
     DartType representationType;
     String representationName;
     if (representationFieldBuilder != null) {
@@ -312,6 +298,9 @@ class SourceExtensionTypeDeclarationBuilder
     }
     _extensionTypeDeclaration.declaredRepresentationType = representationType;
     _extensionTypeDeclaration.representationName = representationName;
+    buildInternal(coreLibrary, addMembersToLibrary: addMembersToLibrary);
+
+    return _extensionTypeDeclaration;
   }
 
   bool _checkRepresentationDependency(

pkg/front_end/test/fasta/type_inference/type_schema_environment_nnbd_test.dart

@@ -1524,7 +1524,9 @@ class TypeSchemaEnvironmentTest extends TypeSchemaEnvironmentTestBase {
   void test_upper_bound_extension_type() {
     parseTestLibrary("extension type E1(Object? it); "
         "extension type E2(Object it);"
-        "extension type E3<X>(X it);");
+        "extension type E3<X>(X it); "
+        "extension type E4(Object it) implements Object; "
+        "extension type E5<X extends Object>(X it) implements Object;");
     checkUpperBound(type1: "E1", type2: "E1", upperBound: "E1");
     checkUpperBound(type1: "E2", type2: "E2", upperBound: "E2");
     checkUpperBound(type1: "E1", type2: "E2", upperBound: "Object?");
@@ -1532,7 +1534,8 @@ class TypeSchemaEnvironmentTest extends TypeSchemaEnvironmentTestBase {
     checkUpperBound(type1: "E1", type2: "E3<num?>", upperBound: "Object?");
     checkUpperBound(type1: "E2", type2: "E3<Object?>", upperBound: "Object?");
     checkUpperBound(type1: "E2", type2: "E3<num?>", upperBound: "Object?");
-    checkUpperBound(type1: "E2", type2: "E3<Object>", upperBound: "Object");
+    checkUpperBound(type1: "E2", type2: "E3<Object>", upperBound: "Object?");
+    checkUpperBound(type1: "E4", type2: "E5<Object>", upperBound: "Object");
   }
 
   void test_upper_bound_extension_type_implements() {
@@ -1546,7 +1549,8 @@ class TypeSchemaEnvironmentTest extends TypeSchemaEnvironmentTestBase {
         "extension type E8(bool it); "
         "extension type E9(int it) implements E6; "
         "extension type E10(double it) implements E5; "
-        "extension type E11<X>(X it); ");
+        "extension type E11<X>(X it); "
+        "extension type E12(bool it) implements Object;");
     checkUpperBound(type1: "E1", type2: "E2", upperBound: "num");
     checkUpperBound(type1: "E1", type2: "E3<int>", upperBound: "num");
     checkUpperBound(type1: "E2", type2: "E3<double>", upperBound: "num");
@@ -1557,7 +1561,8 @@ class TypeSchemaEnvironmentTest extends TypeSchemaEnvironmentTestBase {
     checkUpperBound(type1: "E1", type2: "E6", upperBound: "Object?");
     checkUpperBound(type1: "E2", type2: "E6", upperBound: "Object?");
     checkUpperBound(type1: "E1", type2: "E7", upperBound: "Object");
-    checkUpperBound(type1: "E1", type2: "E8", upperBound: "Object");
+    checkUpperBound(type1: "E1", type2: "E8", upperBound: "Object?");
+    checkUpperBound(type1: "E1", type2: "E12", upperBound: "Object");
     checkUpperBound(type1: "E6", type2: "E9", upperBound: "E6");
     checkUpperBound(type1: "E5", type2: "E9", upperBound: "E5");
     checkUpperBound(type1: "E5", type2: "E6", upperBound: "E5");
@@ -1580,16 +1585,19 @@ class TypeSchemaEnvironmentTest extends TypeSchemaEnvironmentTestBase {
         "extension type E2(num it); "
         "extension type E3(num? it) implements E1; "
         "extension type E4(num it) implements num; "
-        "extension type E5<Y extends Object>(Y it) implements A<Y>;");
+        "extension type E5<Y extends Object>(Y it) implements A<Y>; "
+        "extension type E6(num it) implements Object;");
     checkUpperBound(type1: "E1", type2: "num?", upperBound: "Object?");
     checkUpperBound(type1: "E1", type2: "num", upperBound: "Object?");
     checkUpperBound(type1: "E1", type2: "int?", upperBound: "Object?");
     checkUpperBound(type1: "E1", type2: "int", upperBound: "Object?");
 
     checkUpperBound(type1: "E2", type2: "num?", upperBound: "Object?");
-    checkUpperBound(type1: "E2", type2: "num", upperBound: "Object");
+    checkUpperBound(type1: "E2", type2: "num", upperBound: "Object?");
+    checkUpperBound(type1: "E6", type2: "num", upperBound: "Object");
     checkUpperBound(type1: "E2", type2: "int?", upperBound: "Object?");
-    checkUpperBound(type1: "E2", type2: "int", upperBound: "Object");
+    checkUpperBound(type1: "E2", type2: "int", upperBound: "Object?");
+    checkUpperBound(type1: "E6", type2: "int", upperBound: "Object");
 
     checkUpperBound(type1: "E3", type2: "num?", upperBound: "Object?");
     checkUpperBound(type1: "E3", type2: "num", upperBound: "Object?");

pkg/front_end/test/fasta/types/kernel_type_parser_test.dart

@@ -39,16 +39,18 @@ extension GenericExtension<Y> on ExtendedGenericClass<Y>;
 extension TopExtension on dynamic;
 extension GenericTopExtension<Z> on dynamic;
 class ExtendedSubclass extends ExtendedClass;
-extension type NullableExtensionType(Object? it);
-extension type NonNullableExtensionType(Object it);
-extension type GenericExtensionType<T>(T it);
-extension type GenericExtensionSubType<T>(T it) implements GenericExtensionType<T>;
-extension type NonNullableGenericExtensionType<T extends Object>(T it);
+extension type NullableExtensionType(Object it);
+extension type NonNullableExtensionType(Object it) implements Object;
+extension type PotentiallyNullableGenericExtensionType<T>(T it);
+extension type PotentiallyNullableGenericExtensionSubType<T>(T it) implements PotentiallyNullableGenericExtensionType<T>;
+extension type NonNullableGenericExtensionType<T extends Object>(T it) implements Object;
+extension type NonNullableGenericExtensionSubType<T extends Object>(T it) implements NonNullableGenericExtensionType<T>;
 class GenericClass<T>;
 extension type GenericExtensionTypeImplements<T>(GenericClass<T> it) implements GenericClass<T>;
 class SubGenericClass<T> extends GenericClass<T>;
 extension type GenericSubExtensionTypeImplements<T>(SubGenericClass<T> it) implements GenericExtensionTypeImplements<T>, SubGenericClass<T>;
-extension type NestedGenericExtensionType<T>(GenericExtensionType<T> it);
+extension type PotentiallyNullableNestedGenericExtensionType<T>(PotentiallyNullableGenericExtensionType<T> it);
+extension type NonNullableNestedGenericExtensionType<T extends Object>(NonNullableGenericExtensionType<T> it) implements Object;
 """;
 
 const String expectedSdk = """
@@ -116,21 +118,25 @@ extension TopExtension on dynamic {
 }
 extension GenericTopExtension<Z extends self::Object? = dynamic> on dynamic {
 }
-extension type NullableExtensionType(self::Object? it) {
+extension type NullableExtensionType(self::Object it) {
 }
-extension type NonNullableExtensionType(self::Object it) {
+extension type NonNullableExtensionType(self::Object it) implements self::Object {
 }
-extension type GenericExtensionType<T extends self::Object? = dynamic>(T% it) {
+extension type PotentiallyNullableGenericExtensionType<T extends self::Object? = dynamic>(T% it) {
 }
-extension type GenericExtensionSubType<T extends self::Object? = dynamic>(T% it) implements self::GenericExtensionType<T%> /* = T% */ {
+extension type PotentiallyNullableGenericExtensionSubType<T extends self::Object? = dynamic>(T% it) implements self::PotentiallyNullableGenericExtensionType<T%> /* = T% */ {
 }
-extension type NonNullableGenericExtensionType<T extends self::Object>(T it) {
+extension type NonNullableGenericExtensionType<T extends self::Object>(T it) implements self::Object {
+}
+extension type NonNullableGenericExtensionSubType<T extends self::Object>(T it) implements self::NonNullableGenericExtensionType<T> /* = T */ {
 }
 extension type GenericExtensionTypeImplements<T extends self::Object? = dynamic>(self::GenericClass<T%> it) implements self::GenericClass<T%> {
 }
 extension type GenericSubExtensionTypeImplements<T extends self::Object? = dynamic>(self::SubGenericClass<T%> it) implements self::GenericExtensionTypeImplements<T%> /* = self::GenericClass<T%> */, self::SubGenericClass<T%> {
 }
-extension type NestedGenericExtensionType<T extends self::Object? = dynamic>(self::GenericExtensionType<T%> /* = T% */ it) {
+extension type PotentiallyNullableNestedGenericExtensionType<T extends self::Object? = dynamic>(self::PotentiallyNullableGenericExtensionType<T%> /* = T% */ it) {
+}
+extension type NonNullableNestedGenericExtensionType<T extends self::Object>(self::NonNullableGenericExtensionType<T> /* = T */ it) implements self::Object {
 }
 """;
 

pkg/front_end/test/fasta/types/shared_type_tests.dart

@@ -1268,12 +1268,13 @@ abstract class SubtypeTest<T, E> {
     // Tests for extension types.
     isSubtype("Never", "NullableExtensionType");
     isSubtype("Never", "NonNullableExtensionType");
-    isSubtype("Never", "GenericExtensionType<Object>");
-    isSubtype("Never", "GenericExtensionSubType<Object>");
+    isSubtype("Never", "PotentiallyNullableGenericExtensionType<Object>");
+    isSubtype("Never", "PotentiallyNullableGenericExtensionSubType<Object>");
     isSubtype("Never", "NonNullableGenericExtensionType<Object>");
     isSubtype("Never", "GenericExtensionTypeImplements<Object>");
     isSubtype("Never", "GenericSubExtensionTypeImplements<Object>");
-    isSubtype("Never", "NestedGenericExtensionType<Object>");
+    isSubtype("Never", "PotentiallyNullableNestedGenericExtensionType<Object>");
+    isSubtype("Never", "NonNullableNestedGenericExtensionType<Object>");
 
     isSubtype("NullableExtensionType", "dynamic");
     isSubtype("NullableExtensionType", "void");
@@ -1289,28 +1290,32 @@ abstract class SubtypeTest<T, E> {
     isSubtype("NonNullableExtensionType", "Object");
     isObliviousSubtype("NonNullableExtensionType?", "Object");
 
-    isSubtype("GenericExtensionType<Object>", "dynamic");
-    isSubtype("GenericExtensionType<Object>", "void");
-    isSubtype("GenericExtensionType<Object>", "Object?");
-    isSubtype("GenericExtensionType<Object>", "FutureOr<dynamic>");
-    isSubtype("GenericExtensionType<Object>", "Object");
-    isObliviousSubtype("GenericExtensionType<Object>?", "Object");
+    isSubtype("PotentiallyNullableGenericExtensionType<Object>", "dynamic");
+    isSubtype("PotentiallyNullableGenericExtensionType<Object>", "void");
+    isSubtype("PotentiallyNullableGenericExtensionType<Object>", "Object?");
+    isSubtype(
+        "PotentiallyNullableGenericExtensionType<Object>", "FutureOr<dynamic>");
+    isSubtype("NonNullableGenericExtensionType<Object>", "Object");
+    isObliviousSubtype(
+        "PotentiallyNullableGenericExtensionType<Object>?", "Object");
 
-    isObliviousSubtype("GenericExtensionType<T>", "Object",
+    isObliviousSubtype("PotentiallyNullableGenericExtensionType<T>", "Object",
         typeParameters: "T");
-    isObliviousSubtype("GenericExtensionType<T>?", "Object",
+    isObliviousSubtype("PotentiallyNullableGenericExtensionType<T>?", "Object",
         typeParameters: "T");
-    isSubtype("GenericExtensionType<T>", "Object",
+    isSubtype("NonNullableGenericExtensionType<T>", "Object",
         typeParameters: "T extends Object");
-    isObliviousSubtype("GenericExtensionType<T>?", "Object",
+    isObliviousSubtype("PotentiallyNullableGenericExtensionType<T>?", "Object",
         typeParameters: "T extends Object");
 
-    isSubtype("GenericExtensionSubType<Object>", "dynamic");
-    isSubtype("GenericExtensionSubType<Object>", "void");
-    isSubtype("GenericExtensionSubType<Object>", "Object?");
-    isSubtype("GenericExtensionSubType<Object>", "FutureOr<dynamic>");
-    isSubtype("GenericExtensionSubType<Object>", "Object");
-    isObliviousSubtype("GenericExtensionSubType<Object>?", "Object");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<Object>", "dynamic");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<Object>", "void");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<Object>", "Object?");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<Object>",
+        "FutureOr<dynamic>");
+    isSubtype("NonNullableGenericExtensionSubType<Object>", "Object");
+    isObliviousSubtype(
+        "PotentiallyNullableGenericExtensionSubType<Object>?", "Object");
 
     isSubtype("NonNullableGenericExtensionType<Object>", "dynamic");
     isSubtype("NonNullableGenericExtensionType<Object>", "void");
@@ -1333,20 +1338,45 @@ abstract class SubtypeTest<T, E> {
     isSubtype("GenericSubExtensionTypeImplements<Object>", "Object");
     isObliviousSubtype("GenericSubExtensionTypeImplements<Object>?", "Object");
 
-    isSubtype("NestedGenericExtensionType<Object>", "dynamic");
-    isSubtype("NestedGenericExtensionType<Object>", "void");
-    isSubtype("NestedGenericExtensionType<Object>", "Object?");
-    isSubtype("NestedGenericExtensionType<Object>", "FutureOr<dynamic>");
-    isSubtype("NestedGenericExtensionType<Object>", "Object");
-    isObliviousSubtype("NestedGenericExtensionType<Object>?", "Object");
+    isSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<Object>", "dynamic");
+    isSubtype("NonNullableNestedGenericExtensionType<Object>", "dynamic");
+    isSubtype("PotentiallyNullableNestedGenericExtensionType<Object>", "void");
+    isSubtype("NonNullableNestedGenericExtensionType<Object>", "void");
+    isSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<Object>", "Object?");
+    isSubtype("NonNullableNestedGenericExtensionType<Object>", "Object?");
+    isSubtype("PotentiallyNullableNestedGenericExtensionType<Object>",
+        "FutureOr<dynamic>");
+    isSubtype(
+        "NonNullableNestedGenericExtensionType<Object>", "FutureOr<dynamic>");
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<Object>", "Object");
+    isSubtype("NonNullableNestedGenericExtensionType<Object>", "Object");
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<Object>?", "Object");
+    isObliviousSubtype(
+        "NonNullableNestedGenericExtensionType<Object>?", "Object");
 
-    isObliviousSubtype("NestedGenericExtensionType<T>", "Object",
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<T>", "Object",
         typeParameters: "T");
-    isObliviousSubtype("NestedGenericExtensionType<T>?", "Object",
-        typeParameters: "T");
-    isSubtype("NestedGenericExtensionType<T>", "Object",
+    isSubtype("NonNullableNestedGenericExtensionType<T>", "Object",
         typeParameters: "T extends Object");
-    isObliviousSubtype("NestedGenericExtensionType<T>?", "Object",
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<T>?", "Object",
+        typeParameters: "T");
+    isObliviousSubtype("NonNullableNestedGenericExtensionType<T>?", "Object",
+        typeParameters: "T extends Object");
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<T>", "Object",
+        typeParameters: "T extends Object");
+    isSubtype("NonNullableNestedGenericExtensionType<T>", "Object",
+        typeParameters: "T extends Object");
+    isObliviousSubtype(
+        "PotentiallyNullableNestedGenericExtensionType<T>?", "Object",
+        typeParameters: "T extends Object");
+    isObliviousSubtype("NonNullableNestedGenericExtensionType<T>?", "Object",
         typeParameters: "T extends Object");
 
     isNotSubtype("dynamic", "NullableExtensionType");
@@ -1370,15 +1400,19 @@ abstract class SubtypeTest<T, E> {
     isObliviousSubtype("GenericExtensionTypeImplements<Object>?", "Object");
     isObliviousSubtype("GenericSubExtensionTypeImplements<Object>?", "Object");
 
-    isSubtype("GenericExtensionType<Object>", "GenericExtensionType<Object>");
-    isSubtype("GenericExtensionType<num>", "GenericExtensionType<Object>");
-    isNotSubtype("GenericExtensionType<Object>", "GenericExtensionType<num>");
+    isSubtype("PotentiallyNullableGenericExtensionType<Object>",
+        "PotentiallyNullableGenericExtensionType<Object>");
+    isSubtype("PotentiallyNullableGenericExtensionType<num>",
+        "PotentiallyNullableGenericExtensionType<Object>");
+    isNotSubtype("PotentiallyNullableGenericExtensionType<Object>",
+        "PotentiallyNullableGenericExtensionType<num>");
 
-    isSubtype(
-        "GenericExtensionSubType<Object>", "GenericExtensionType<Object>");
-    isSubtype("GenericExtensionSubType<num>", "GenericExtensionType<Object>");
-    isNotSubtype(
-        "GenericExtensionSubType<Object>", "GenericExtensionType<num>");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<Object>",
+        "PotentiallyNullableGenericExtensionType<Object>");
+    isSubtype("PotentiallyNullableGenericExtensionSubType<num>",
+        "PotentiallyNullableGenericExtensionType<Object>");
+    isNotSubtype("PotentiallyNullableGenericExtensionSubType<Object>",
+        "PotentiallyNullableGenericExtensionType<num>");
 
     isSubtype("GenericExtensionTypeImplements<Object>", "GenericClass<Object>");
     isSubtype("GenericExtensionTypeImplements<num>", "GenericClass<Object>");
@@ -1404,7 +1438,9 @@ abstract class SubtypeTest<T, E> {
     isNotSubtype(
         "GenericSubExtensionTypeImplements<Object>", "SubGenericClass<num>");
 
-    isNotSubtype(
-        "NestedGenericExtensionType<Object>", "GenericExtensionType<Object>");
+    isNotSubtype("PotentiallyNullableNestedGenericExtensionType<Object>",
+        "PotentiallyNullableGenericExtensionType<Object>");
+    isNotSubtype("NonNullableNestedGenericExtensionType<Object>",
+        "NonNullableGenericExtensionType<Object>");
   }
 }

pkg/front_end/testcases/dart2js/extension_types/external.dart.strong.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dart2js/extension_types/external.dart.strong.transformed.expect

@@ -63,9 +63,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => js_2::_callMethodUnchecked0<self::A>(#this, "method");
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => js_2::callMethod<T>(#this, "genericMethod", <dynamic>[t]);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => js_2::callMethod<T%>(#this, "genericMethod", <dynamic>[t]);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -73,7 +73,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;
@@ -84,14 +84,14 @@ static method method(self::A a) → void {
   a = js_2::getProperty<self::A>(b1, "field");
   js_2::setProperty<self::A>(b1, "field", a);
   a = js_2::_callMethodUnchecked0<self::A>(b1, "method");
-  b2 = js_2::callMethod<self::B /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(b2, "getter");
   js_2::setProperty<self::B /* = self::A */>(b1, "setter", b2);
   js_2::setProperty<self::B /* = self::A */>(b1, "property", js_2::getProperty<self::B /* = self::A */>(b2, "property"));
   a = js_2::getProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField");
   js_2::setProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField", a);
   a = js_2::_callMethodUnchecked0<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticMethod");
-  b2 = js_2::callMethod<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGetter");
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticSetter", b2);
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty", js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty"));

pkg/front_end/testcases/dart2js/extension_types/external.dart.weak.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dart2js/extension_types/external.dart.weak.modular.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dart2js/extension_types/external.dart.weak.outline.expect

@@ -58,9 +58,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -68,7 +68,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dart2js/extension_types/external.dart.weak.transformed.expect

@@ -63,9 +63,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => js_2::_callMethodUnchecked0<self::A>(#this, "method");
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => js_2::callMethod<T>(#this, "genericMethod", <dynamic>[t]);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => js_2::callMethod<T%>(#this, "genericMethod", <dynamic>[t]);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -73,7 +73,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;
@@ -84,14 +84,14 @@ static method method(self::A a) → void {
   a = js_2::getProperty<self::A>(b1, "field");
   js_2::setProperty<self::A>(b1, "field", a);
   a = js_2::_callMethodUnchecked0<self::A>(b1, "method");
-  b2 = js_2::callMethod<self::B /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(b2, "getter");
   js_2::setProperty<self::B /* = self::A */>(b1, "setter", b2);
   js_2::setProperty<self::B /* = self::A */>(b1, "property", js_2::getProperty<self::B /* = self::A */>(b2, "property"));
   a = js_2::getProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField");
   js_2::setProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField", a);
   a = js_2::_callMethodUnchecked0<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticMethod");
-  b2 = js_2::callMethod<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGetter");
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticSetter", b2);
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty", js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty"));

pkg/front_end/testcases/dartdevc/extension_types/external.dart.strong.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dartdevc/extension_types/external.dart.strong.transformed.expect

@@ -63,9 +63,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => js_2::_callMethodUnchecked0<self::A>(#this, "method");
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => js_2::callMethod<T>(#this, "genericMethod", <dynamic>[t]);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => js_2::callMethod<T%>(#this, "genericMethod", <dynamic>[t]);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -73,7 +73,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;
@@ -84,14 +84,14 @@ static method method(self::A a) → void {
   a = js_2::getProperty<self::A>(b1, "field");
   js_2::setProperty<self::A>(b1, "field", a);
   a = js_2::_callMethodUnchecked0<self::A>(b1, "method");
-  b2 = js_2::callMethod<self::B /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(b2, "getter");
   js_2::setProperty<self::B /* = self::A */>(b1, "setter", b2);
   js_2::setProperty<self::B /* = self::A */>(b1, "property", js_2::getProperty<self::B /* = self::A */>(b2, "property"));
   a = js_2::getProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField");
   js_2::setProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField", a);
   a = js_2::_callMethodUnchecked0<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticMethod");
-  b2 = js_2::callMethod<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGetter");
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticSetter", b2);
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty", js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty"));

pkg/front_end/testcases/dartdevc/extension_types/external.dart.weak.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dartdevc/extension_types/external.dart.weak.modular.expect

@@ -61,9 +61,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -71,7 +71,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dartdevc/extension_types/external.dart.weak.outline.expect

@@ -58,9 +58,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -68,7 +68,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;

pkg/front_end/testcases/dartdevc/extension_types/external.dart.weak.transformed.expect

@@ -63,9 +63,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => js_2::_callMethodUnchecked0<self::A>(#this, "method");
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => js_2::callMethod<T>(#this, "genericMethod", <dynamic>[t]);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => js_2::callMethod<T%>(#this, "genericMethod", <dynamic>[t]);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member method B|get#property(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
@@ -73,7 +73,7 @@ external static extension-type-member method B|set#property(lowered final self::
 external static extension-type-member get B|staticField() → self::A;
 external static extension-type-member set B|staticField(self::A #externalFieldValue) → void;
 external static extension-type-member method B|staticMethod() → self::A;
-external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T t) → self::B|staticGenericMethod::T;
+external static extension-type-member method B|staticGenericMethod<T extends self::B /* = self::A */>(self::B|staticGenericMethod::T% t) → self::B|staticGenericMethod::T%;
 external static extension-type-member get B|staticGetter() → self::B /* = self::A */;
 external static extension-type-member set B|staticSetter(self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticProperty() → self::B /* = self::A */;
@@ -84,14 +84,14 @@ static method method(self::A a) → void {
   a = js_2::getProperty<self::A>(b1, "field");
   js_2::setProperty<self::A>(b1, "field", a);
   a = js_2::_callMethodUnchecked0<self::A>(b1, "method");
-  b2 = js_2::callMethod<self::B /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(b2, "genericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(b2, "getter");
   js_2::setProperty<self::B /* = self::A */>(b1, "setter", b2);
   js_2::setProperty<self::B /* = self::A */>(b1, "property", js_2::getProperty<self::B /* = self::A */>(b2, "property"));
   a = js_2::getProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField");
   js_2::setProperty<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticField", a);
   a = js_2::_callMethodUnchecked0<self::A>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticMethod");
-  b2 = js_2::callMethod<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
+  b2 = js_2::callMethod<self::B% /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGenericMethod", <dynamic>[b2]);
   b1 = js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticGetter");
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticSetter", b2);
   js_2::setProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty", js_2::getProperty<self::B /* = self::A */>(js_2::_getPropertyTrustType<core::Object>(_js2::staticInteropGlobalContext, "B"), "staticProperty"));

pkg/front_end/testcases/extension_types/assign_interface_type.dart

@@ -8,7 +8,9 @@ class B extends A {}
 
 extension type C(Object? o) {}
 
-extension type D(Object o) {}
+extension type D(Object o) implements Object {}
+
+extension type D2(Object o) {}
 
 extension type E(B it) implements A {}
 
@@ -16,26 +18,32 @@ extension type F(B it) implements E, B {}
 
 extension type G<T>(T o) {}
 
-test<T1, T2 extends A>(
+extension type G2<T extends Object>(T o) implements Object {}
+
+test<T1, T2 extends A, T3 extends Object>(
     Object o,
     A a,
     B b,
     C c,
     D d,
+    D2 d2,
     E e,
     F f,
     G<T1> g1,
-    G<T2> g2) {
+    G<T2> g2,
+    G2<T3> g3) {
 
   o = o; // Ok
   o = a; // Ok
   o = b; // Ok
   o = c; // Error
   o = d; // Ok
+  o = d2; // Error
   o = e; // Ok
   o = f; // Ok
   o = g1; // Error
-  o = g2; // Ok
+  o = g2; // Error
+  o = g3; // Ok
 
   a = o; // Error
   a = a; // Ok
@@ -116,4 +124,4 @@ test<T1, T2 extends A>(
   g2 = f; // Error
   g2 = g1; // Error
   g2 = g2; // Ok
-}
+}

pkg/front_end/testcases/extension_types/assign_interface_type.dart.strong.expect

@@ -2,282 +2,292 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = d2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = g2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
 //  - 'Object' is from 'dart:core'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
 //  - 'Object' is from 'dart:core'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
 //  - 'Object' is from 'dart:core'.
 //   c = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
 //   c = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
 //   c = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
 //   c = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
 //   c = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
 //   c = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
 //  - 'Object' is from 'dart:core'.
 //   d = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
 //   d = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
 //   d = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
 //   d = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
 //   d = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
 //   d = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
 //  - 'Object' is from 'dart:core'.
 //   e = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
 //   e = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
 //   e = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
 //   e = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
 //   e = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
 //  - 'Object' is from 'dart:core'.
 //   f = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
 //   f = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
 //   f = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
 //   f = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
 //   f = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
 //   f = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
 //  - 'Object' is from 'dart:core'.
 //   g1 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = g2; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
 //  - 'Object' is from 'dart:core'.
 //   g2 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = g1; // Error
 //        ^
 //
@@ -299,11 +309,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -319,6 +334,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */ {
   lowered final self::C /* = core::Object? */ #this = o;
   return #this;
@@ -331,6 +351,12 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
 }
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */ {
+  lowered final self::D2 /* = core::Object */ #this = o;
+  return #this;
+}
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */ {
   lowered final self::E /* = self::B */ #this = it;
   return #this;
@@ -349,242 +375,256 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
 }
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic {
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ {
+  lowered final self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ #this = o;
+  return #this;
+}
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic {
   o = o;
   o = a;
   o = b;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = c; // Error
       ^" in c as{TypeError} core::Object;
   o = d;
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = d2; // Error
+      ^" in d2 as{TypeError} core::Object;
   o = e;
   o = f;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = g1; // Error
       ^" in g1 as{TypeError} core::Object;
-  o = g2;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = g2; // Error
+      ^" in g2 as{TypeError} core::Object;
+  o = g3;
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
  - 'Object' is from 'dart:core'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = o; // Error
       ^" in o as{TypeError} self::A;
   a = a;
   a = b;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = c; // Error
       ^" in c as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = d; // Error
       ^" in d as{TypeError} self::A;
   a = e;
   a = f;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g1; // Error
       ^" in g1 as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g2; // Error
       ^" in g2 as{TypeError} self::A;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
  - 'Object' is from 'dart:core'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = o; // Error
       ^" in o as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = a; // Error
       ^" in a as{TypeError} self::B;
   b = b;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = c; // Error
       ^" in c as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = d; // Error
       ^" in d as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = e; // Error
       ^" in e as{TypeError} self::B;
   b = f;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g1; // Error
       ^" in g1 as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g2; // Error
       ^" in g2 as{TypeError} self::B;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
  - 'Object' is from 'dart:core'.
   c = o; // Error
       ^" in o as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = a; // Error
       ^" in a as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = b; // Error
       ^" in b as{TypeError} self::C /* = core::Object? */;
   c = c;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
   c = d; // Error
       ^" in d as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
   c = e; // Error
       ^" in e as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
   c = f; // Error
       ^" in f as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
   c = g1; // Error
       ^" in g1 as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
   c = g2; // Error
       ^" in g2 as{TypeError} self::C /* = core::Object? */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
  - 'Object' is from 'dart:core'.
   d = o; // Error
       ^" in o as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = a; // Error
       ^" in a as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = b; // Error
       ^" in b as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
   d = c; // Error
       ^" in c as{TypeError} self::D /* = core::Object */;
   d = d;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
   d = e; // Error
       ^" in e as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
   d = f; // Error
       ^" in f as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
   d = g1; // Error
       ^" in g1 as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
   d = g2; // Error
       ^" in g2 as{TypeError} self::D /* = core::Object */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
  - 'Object' is from 'dart:core'.
   e = o; // Error
       ^" in o as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = a; // Error
       ^" in a as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = b; // Error
       ^" in b as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
   e = c; // Error
       ^" in c as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
   e = d; // Error
       ^" in d as{TypeError} self::E /* = self::B */;
   e = e;
   e = f;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
   e = g1; // Error
       ^" in g1 as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
   e = g2; // Error
       ^" in g2 as{TypeError} self::E /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
  - 'Object' is from 'dart:core'.
   f = o; // Error
       ^" in o as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = a; // Error
       ^" in a as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = b; // Error
       ^" in b as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
   f = c; // Error
       ^" in c as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
   f = d; // Error
       ^" in d as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
   f = e; // Error
       ^" in e as{TypeError} self::F /* = self::B */;
   f = f;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
   f = g1; // Error
       ^" in g1 as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
   f = g2; // Error
       ^" in g2 as{TypeError} self::F /* = self::B */;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
  - 'Object' is from 'dart:core'.
   g1 = o; // Error
        ^" in o as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = a; // Error
        ^" in a as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = b; // Error
        ^" in b as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
   g1 = c; // Error
        ^" in c as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
   g1 = d; // Error
        ^" in d as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
   g1 = e; // Error
        ^" in e as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
   g1 = f; // Error
        ^" in f as{TypeError} Never;
   g1 = g1;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
   g1 = g2; // Error
        ^" in g2 as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
  - 'Object' is from 'dart:core'.
   g2 = o; // Error
        ^" in o as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = a; // Error
        ^" in a as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = b; // Error
        ^" in b as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
   g2 = c; // Error
        ^" in c as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
   g2 = d; // Error
        ^" in d as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
   g2 = e; // Error
        ^" in e as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
   g2 = f; // Error
        ^" in f as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
   g2 = g1; // Error
        ^" in g1 as{TypeError} Never;
   g2 = g2;

pkg/front_end/testcases/extension_types/assign_interface_type.dart.strong.transformed.expect

@@ -2,282 +2,292 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = d2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = g2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
 //  - 'Object' is from 'dart:core'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
 //  - 'Object' is from 'dart:core'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
 //  - 'Object' is from 'dart:core'.
 //   c = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
 //   c = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
 //   c = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
 //   c = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
 //   c = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
 //   c = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
 //  - 'Object' is from 'dart:core'.
 //   d = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
 //   d = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
 //   d = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
 //   d = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
 //   d = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
 //   d = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
 //  - 'Object' is from 'dart:core'.
 //   e = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
 //   e = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
 //   e = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
 //   e = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
 //   e = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
 //  - 'Object' is from 'dart:core'.
 //   f = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
 //   f = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
 //   f = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
 //   f = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
 //   f = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
 //   f = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
 //  - 'Object' is from 'dart:core'.
 //   g1 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = g2; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
 //  - 'Object' is from 'dart:core'.
 //   g2 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = g1; // Error
 //        ^
 //
@@ -299,11 +309,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -319,6 +334,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */ {
   lowered final self::C /* = core::Object? */ #this = o;
   return #this;
@@ -331,6 +351,12 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
 }
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */ {
+  lowered final self::D2 /* = core::Object */ #this = o;
+  return #this;
+}
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */ {
   lowered final self::E /* = self::B */ #this = it;
   return #this;
@@ -349,242 +375,256 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
 }
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic {
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ {
+  lowered final self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ #this = o;
+  return #this;
+}
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic {
   o = o;
   o = a;
   o = b;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = c; // Error
       ^" in let self::C /* = core::Object? */ #t1 = c in #t1 == null ?{core::Object} #t1 as{TypeError} core::Object : #t1{core::Object};
   o = d;
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = d2; // Error
+      ^" in let self::D2 /* = core::Object */ #t2 = d2 in #t2 == null ?{core::Object} #t2 as{TypeError} core::Object : #t2{core::Object};
   o = e;
   o = f;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = g1; // Error
-      ^" in let self::G<self::test::T1%> /* = self::test::T1% */ #t2 = g1 in #t2 == null ?{core::Object} #t2 as{TypeError} core::Object : #t2{core::Object};
-  o = g2;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+      ^" in let self::G<self::test::T1%> /* = self::test::T1% */ #t3 = g1 in #t3 == null ?{core::Object} #t3 as{TypeError} core::Object : #t3{core::Object};
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = g2; // Error
+      ^" in let self::G<self::test::T2> /* = self::test::T2 */ #t4 = g2 in #t4 == null ?{core::Object} #t4 as{TypeError} core::Object : #t4{core::Object};
+  o = g3;
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
  - 'Object' is from 'dart:core'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = o; // Error
       ^" in o as{TypeError} self::A;
   a = a;
   a = b;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = c; // Error
       ^" in c as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = d; // Error
       ^" in d as{TypeError} self::A;
   a = e;
   a = f;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g1; // Error
       ^" in g1 as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g2; // Error
       ^" in g2 as{TypeError} self::A;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
  - 'Object' is from 'dart:core'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = o; // Error
       ^" in o as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = a; // Error
       ^" in a as{TypeError} self::B;
   b = b;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = c; // Error
       ^" in c as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = d; // Error
       ^" in d as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = e; // Error
       ^" in e as{TypeError} self::B;
   b = f;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g1; // Error
       ^" in g1 as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g2; // Error
       ^" in g2 as{TypeError} self::B;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
  - 'Object' is from 'dart:core'.
   c = o; // Error
       ^" in o as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = a; // Error
       ^" in a as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = b; // Error
       ^" in b as{TypeError} self::C /* = core::Object? */;
   c = c;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
   c = d; // Error
       ^" in d as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
   c = e; // Error
       ^" in e as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
   c = f; // Error
       ^" in f as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
   c = g1; // Error
       ^" in g1 as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
   c = g2; // Error
       ^" in g2 as{TypeError} self::C /* = core::Object? */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
  - 'Object' is from 'dart:core'.
   d = o; // Error
       ^" in o as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = a; // Error
       ^" in a as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = b; // Error
       ^" in b as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
   d = c; // Error
       ^" in c as{TypeError} self::D /* = core::Object */;
   d = d;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
   d = e; // Error
       ^" in e as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
   d = f; // Error
       ^" in f as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
   d = g1; // Error
       ^" in g1 as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
   d = g2; // Error
       ^" in g2 as{TypeError} self::D /* = core::Object */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
  - 'Object' is from 'dart:core'.
   e = o; // Error
       ^" in o as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = a; // Error
       ^" in a as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = b; // Error
       ^" in b as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
   e = c; // Error
       ^" in c as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
   e = d; // Error
       ^" in d as{TypeError} self::E /* = self::B */;
   e = e;
   e = f;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
   e = g1; // Error
       ^" in g1 as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
   e = g2; // Error
       ^" in g2 as{TypeError} self::E /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
  - 'Object' is from 'dart:core'.
   f = o; // Error
       ^" in o as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = a; // Error
       ^" in a as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = b; // Error
       ^" in b as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
   f = c; // Error
       ^" in c as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
   f = d; // Error
       ^" in d as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
   f = e; // Error
       ^" in e as{TypeError} self::F /* = self::B */;
   f = f;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
   f = g1; // Error
       ^" in g1 as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
   f = g2; // Error
       ^" in g2 as{TypeError} self::F /* = self::B */;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
  - 'Object' is from 'dart:core'.
   g1 = o; // Error
        ^" in o as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = a; // Error
        ^" in a as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = b; // Error
        ^" in b as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
   g1 = c; // Error
        ^" in c as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
   g1 = d; // Error
        ^" in d as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
   g1 = e; // Error
        ^" in e as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
   g1 = f; // Error
        ^" in f as{TypeError} Never;
   g1 = g1;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
   g1 = g2; // Error
        ^" in g2 as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
  - 'Object' is from 'dart:core'.
   g2 = o; // Error
        ^" in o as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = a; // Error
        ^" in a as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = b; // Error
        ^" in b as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
   g2 = c; // Error
        ^" in c as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
   g2 = d; // Error
        ^" in d as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
   g2 = e; // Error
        ^" in e as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
   g2 = f; // Error
        ^" in f as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
   g2 = g1; // Error
        ^" in g1 as{TypeError} Never;
   g2 = g2;

pkg/front_end/testcases/extension_types/assign_interface_type.dart.textual_outline.expect

@@ -3,9 +3,11 @@ class A {}
 class B extends A {}
 
 extension type C(Object? o) {}
-extension type D(Object o) {}
+extension type D(Object o) implements Object {}
+extension type D2(Object o) {}
 extension type E(B it) implements A {}
 extension type F(B it) implements E, B {}
 extension type G<T>(T o) {}
-test<T1, T2 extends A>(
-    Object o, A a, B b, C c, D d, E e, F f, G<T1> g1, G<T2> g2) {}
+extension type G2<T extends Object>(T o) implements Object {}
+test<T1, T2 extends A, T3 extends Object>(Object o, A a, B b, C c, D d, D2 d2,
+    E e, F f, G<T1> g1, G<T2> g2, G2<T3> g3) {}

pkg/front_end/testcases/extension_types/assign_interface_type.dart.textual_outline_modelled.expect

@@ -3,9 +3,11 @@ class A {}
 class B extends A {}
 
 extension type C(Object? o) {}
-extension type D(Object o) {}
+extension type D(Object o) implements Object {}
+extension type D2(Object o) {}
 extension type E(B it) implements A {}
 extension type F(B it) implements E, B {}
 extension type G<T>(T o) {}
-test<T1, T2 extends A>(
-    Object o, A a, B b, C c, D d, E e, F f, G<T1> g1, G<T2> g2) {}
+extension type G2<T extends Object>(T o) implements Object {}
+test<T1, T2 extends A, T3 extends Object>(Object o, A a, B b, C c, D d, D2 d2,
+    E e, F f, G<T1> g1, G<T2> g2, G2<T3> g3) {}

pkg/front_end/testcases/extension_types/assign_interface_type.dart.weak.expect

@@ -2,282 +2,292 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = d2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = g2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
 //  - 'Object' is from 'dart:core'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
 //  - 'Object' is from 'dart:core'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
 //  - 'Object' is from 'dart:core'.
 //   c = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
 //   c = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
 //   c = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
 //   c = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
 //   c = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
 //   c = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
 //  - 'Object' is from 'dart:core'.
 //   d = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
 //   d = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
 //   d = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
 //   d = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
 //   d = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
 //   d = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
 //  - 'Object' is from 'dart:core'.
 //   e = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
 //   e = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
 //   e = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
 //   e = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
 //   e = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
 //  - 'Object' is from 'dart:core'.
 //   f = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
 //   f = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
 //   f = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
 //   f = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
 //   f = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
 //   f = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
 //  - 'Object' is from 'dart:core'.
 //   g1 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = g2; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
 //  - 'Object' is from 'dart:core'.
 //   g2 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = g1; // Error
 //        ^
 //
@@ -299,11 +309,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -319,6 +334,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */ {
   lowered final self::C /* = core::Object? */ #this = o;
   return #this;
@@ -331,6 +351,12 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
 }
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */ {
+  lowered final self::D2 /* = core::Object */ #this = o;
+  return #this;
+}
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */ {
   lowered final self::E /* = self::B */ #this = it;
   return #this;
@@ -349,242 +375,256 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
 }
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic {
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ {
+  lowered final self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ #this = o;
+  return #this;
+}
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic {
   o = o;
   o = a;
   o = b;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = c; // Error
       ^" in c as{TypeError} core::Object;
   o = d;
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = d2; // Error
+      ^" in d2 as{TypeError} core::Object;
   o = e;
   o = f;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = g1; // Error
       ^" in g1 as{TypeError} core::Object;
-  o = g2;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = g2; // Error
+      ^" in g2 as{TypeError} core::Object;
+  o = g3;
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
  - 'Object' is from 'dart:core'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = o; // Error
       ^" in o as{TypeError} self::A;
   a = a;
   a = b;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = c; // Error
       ^" in c as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = d; // Error
       ^" in d as{TypeError} self::A;
   a = e;
   a = f;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g1; // Error
       ^" in g1 as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g2; // Error
       ^" in g2 as{TypeError} self::A;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
  - 'Object' is from 'dart:core'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = o; // Error
       ^" in o as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = a; // Error
       ^" in a as{TypeError} self::B;
   b = b;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = c; // Error
       ^" in c as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = d; // Error
       ^" in d as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = e; // Error
       ^" in e as{TypeError} self::B;
   b = f;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g1; // Error
       ^" in g1 as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g2; // Error
       ^" in g2 as{TypeError} self::B;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
  - 'Object' is from 'dart:core'.
   c = o; // Error
       ^" in o as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = a; // Error
       ^" in a as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = b; // Error
       ^" in b as{TypeError} self::C /* = core::Object? */;
   c = c;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
   c = d; // Error
       ^" in d as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
   c = e; // Error
       ^" in e as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
   c = f; // Error
       ^" in f as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
   c = g1; // Error
       ^" in g1 as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
   c = g2; // Error
       ^" in g2 as{TypeError} self::C /* = core::Object? */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
  - 'Object' is from 'dart:core'.
   d = o; // Error
       ^" in o as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = a; // Error
       ^" in a as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = b; // Error
       ^" in b as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
   d = c; // Error
       ^" in c as{TypeError} self::D /* = core::Object */;
   d = d;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
   d = e; // Error
       ^" in e as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
   d = f; // Error
       ^" in f as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
   d = g1; // Error
       ^" in g1 as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
   d = g2; // Error
       ^" in g2 as{TypeError} self::D /* = core::Object */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
  - 'Object' is from 'dart:core'.
   e = o; // Error
       ^" in o as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = a; // Error
       ^" in a as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = b; // Error
       ^" in b as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
   e = c; // Error
       ^" in c as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
   e = d; // Error
       ^" in d as{TypeError} self::E /* = self::B */;
   e = e;
   e = f;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
   e = g1; // Error
       ^" in g1 as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
   e = g2; // Error
       ^" in g2 as{TypeError} self::E /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
  - 'Object' is from 'dart:core'.
   f = o; // Error
       ^" in o as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = a; // Error
       ^" in a as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = b; // Error
       ^" in b as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
   f = c; // Error
       ^" in c as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
   f = d; // Error
       ^" in d as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
   f = e; // Error
       ^" in e as{TypeError} self::F /* = self::B */;
   f = f;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
   f = g1; // Error
       ^" in g1 as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
   f = g2; // Error
       ^" in g2 as{TypeError} self::F /* = self::B */;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
  - 'Object' is from 'dart:core'.
   g1 = o; // Error
        ^" in o as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = a; // Error
        ^" in a as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = b; // Error
        ^" in b as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
   g1 = c; // Error
        ^" in c as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
   g1 = d; // Error
        ^" in d as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
   g1 = e; // Error
        ^" in e as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
   g1 = f; // Error
        ^" in f as{TypeError} Never;
   g1 = g1;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
   g1 = g2; // Error
        ^" in g2 as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
  - 'Object' is from 'dart:core'.
   g2 = o; // Error
        ^" in o as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = a; // Error
        ^" in a as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = b; // Error
        ^" in b as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
   g2 = c; // Error
        ^" in c as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
   g2 = d; // Error
        ^" in d as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
   g2 = e; // Error
        ^" in e as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
   g2 = f; // Error
        ^" in f as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
   g2 = g1; // Error
        ^" in g1 as{TypeError} Never;
   g2 = g2;

pkg/front_end/testcases/extension_types/assign_interface_type.dart.weak.modular.expect

@@ -2,282 +2,292 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = d2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = g2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
 //  - 'Object' is from 'dart:core'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
 //  - 'Object' is from 'dart:core'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
 //  - 'Object' is from 'dart:core'.
 //   c = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
 //   c = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
 //   c = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
 //   c = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
 //   c = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
 //   c = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
 //  - 'Object' is from 'dart:core'.
 //   d = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
 //   d = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
 //   d = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
 //   d = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
 //   d = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
 //   d = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
 //  - 'Object' is from 'dart:core'.
 //   e = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
 //   e = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
 //   e = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
 //   e = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
 //   e = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
 //  - 'Object' is from 'dart:core'.
 //   f = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
 //   f = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
 //   f = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
 //   f = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
 //   f = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
 //   f = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
 //  - 'Object' is from 'dart:core'.
 //   g1 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = g2; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
 //  - 'Object' is from 'dart:core'.
 //   g2 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = g1; // Error
 //        ^
 //
@@ -299,11 +309,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -319,6 +334,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */ {
   lowered final self::C /* = core::Object? */ #this = o;
   return #this;
@@ -331,6 +351,12 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
 }
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */ {
+  lowered final self::D2 /* = core::Object */ #this = o;
+  return #this;
+}
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */ {
   lowered final self::E /* = self::B */ #this = it;
   return #this;
@@ -349,242 +375,256 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
 }
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic {
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ {
+  lowered final self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ #this = o;
+  return #this;
+}
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic {
   o = o;
   o = a;
   o = b;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = c; // Error
       ^" in c as{TypeError} core::Object;
   o = d;
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = d2; // Error
+      ^" in d2 as{TypeError} core::Object;
   o = e;
   o = f;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = g1; // Error
       ^" in g1 as{TypeError} core::Object;
-  o = g2;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = g2; // Error
+      ^" in g2 as{TypeError} core::Object;
+  o = g3;
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
  - 'Object' is from 'dart:core'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = o; // Error
       ^" in o as{TypeError} self::A;
   a = a;
   a = b;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = c; // Error
       ^" in c as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = d; // Error
       ^" in d as{TypeError} self::A;
   a = e;
   a = f;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g1; // Error
       ^" in g1 as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g2; // Error
       ^" in g2 as{TypeError} self::A;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
  - 'Object' is from 'dart:core'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = o; // Error
       ^" in o as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = a; // Error
       ^" in a as{TypeError} self::B;
   b = b;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = c; // Error
       ^" in c as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = d; // Error
       ^" in d as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = e; // Error
       ^" in e as{TypeError} self::B;
   b = f;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g1; // Error
       ^" in g1 as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g2; // Error
       ^" in g2 as{TypeError} self::B;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
  - 'Object' is from 'dart:core'.
   c = o; // Error
       ^" in o as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = a; // Error
       ^" in a as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = b; // Error
       ^" in b as{TypeError} self::C /* = core::Object? */;
   c = c;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
   c = d; // Error
       ^" in d as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
   c = e; // Error
       ^" in e as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
   c = f; // Error
       ^" in f as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
   c = g1; // Error
       ^" in g1 as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
   c = g2; // Error
       ^" in g2 as{TypeError} self::C /* = core::Object? */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
  - 'Object' is from 'dart:core'.
   d = o; // Error
       ^" in o as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = a; // Error
       ^" in a as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = b; // Error
       ^" in b as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
   d = c; // Error
       ^" in c as{TypeError} self::D /* = core::Object */;
   d = d;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
   d = e; // Error
       ^" in e as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
   d = f; // Error
       ^" in f as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
   d = g1; // Error
       ^" in g1 as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
   d = g2; // Error
       ^" in g2 as{TypeError} self::D /* = core::Object */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
  - 'Object' is from 'dart:core'.
   e = o; // Error
       ^" in o as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = a; // Error
       ^" in a as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = b; // Error
       ^" in b as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
   e = c; // Error
       ^" in c as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
   e = d; // Error
       ^" in d as{TypeError} self::E /* = self::B */;
   e = e;
   e = f;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
   e = g1; // Error
       ^" in g1 as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
   e = g2; // Error
       ^" in g2 as{TypeError} self::E /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
  - 'Object' is from 'dart:core'.
   f = o; // Error
       ^" in o as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = a; // Error
       ^" in a as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = b; // Error
       ^" in b as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
   f = c; // Error
       ^" in c as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
   f = d; // Error
       ^" in d as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
   f = e; // Error
       ^" in e as{TypeError} self::F /* = self::B */;
   f = f;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
   f = g1; // Error
       ^" in g1 as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
   f = g2; // Error
       ^" in g2 as{TypeError} self::F /* = self::B */;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
  - 'Object' is from 'dart:core'.
   g1 = o; // Error
        ^" in o as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = a; // Error
        ^" in a as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = b; // Error
        ^" in b as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
   g1 = c; // Error
        ^" in c as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
   g1 = d; // Error
        ^" in d as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
   g1 = e; // Error
        ^" in e as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
   g1 = f; // Error
        ^" in f as{TypeError} Never;
   g1 = g1;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
   g1 = g2; // Error
        ^" in g2 as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
  - 'Object' is from 'dart:core'.
   g2 = o; // Error
        ^" in o as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = a; // Error
        ^" in a as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = b; // Error
        ^" in b as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
   g2 = c; // Error
        ^" in c as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
   g2 = d; // Error
        ^" in d as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
   g2 = e; // Error
        ^" in e as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
   g2 = f; // Error
        ^" in f as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
   g2 = g1; // Error
        ^" in g1 as{TypeError} Never;
   g2 = g2;

pkg/front_end/testcases/extension_types/assign_interface_type.dart.weak.outline.expect

@@ -15,11 +15,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -35,6 +40,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */
   ;
 static extension-type-member method C|constructor#_#new#tearOff(core::Object? o) → self::C /* = core::Object? */
@@ -43,6 +53,10 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
   ;
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */
+  ;
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */
   ;
 static extension-type-member method E|constructor#_#new#tearOff(self::B it) → self::E /* = self::B */
@@ -55,5 +69,9 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
   ;
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */
+  ;
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic
   ;

pkg/front_end/testcases/extension_types/assign_interface_type.dart.weak.transformed.expect

@@ -2,282 +2,292 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = d2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
 //  - 'Object' is from 'dart:core'.
 //   o = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+//  - 'Object' is from 'dart:core'.
+//   o = g2; // Error
+//       ^
+//
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
 //  - 'Object' is from 'dart:core'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   a = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
 //  - 'Object' is from 'dart:core'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   b = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
 //  - 'Object' is from 'dart:core'.
 //   c = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   c = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
 //   c = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
 //   c = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
 //   c = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
 //   c = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
 //   c = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
 //  - 'Object' is from 'dart:core'.
 //   d = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   d = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
 //   d = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
 //   d = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
 //   d = f; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
 //   d = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
 //   d = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
 //  - 'Object' is from 'dart:core'.
 //   e = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   e = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
 //   e = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
 //   e = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
 //   e = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
 //   e = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
 //  - 'Object' is from 'dart:core'.
 //   f = o; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = a; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   f = b; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
 //   f = c; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
 //   f = d; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
 //   f = e; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
 //   f = g1; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
 //   f = g2; // Error
 //       ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
 //  - 'Object' is from 'dart:core'.
 //   g1 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g1 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
 //   g1 = g2; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
 //  - 'Object' is from 'dart:core'.
 //   g2 = o; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
 //  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = a; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
 //  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
 //   g2 = b; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = c; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = d; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = e; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = f; // Error
 //        ^
 //
-// pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+// pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
 //   g2 = g1; // Error
 //        ^
 //
@@ -299,11 +309,16 @@ extension type C(core::Object? o) {
   constructor • = self::C|constructor#;
   constructor tearoff • = self::C|constructor#_#new#tearOff;
 }
-extension type D(core::Object o) {
+extension type D(core::Object o) implements core::Object {
   abstract extension-type-member representation-field get o() → core::Object;
   constructor • = self::D|constructor#;
   constructor tearoff • = self::D|constructor#_#new#tearOff;
 }
+extension type D2(core::Object o) {
+  abstract extension-type-member representation-field get o() → core::Object;
+  constructor • = self::D2|constructor#;
+  constructor tearoff • = self::D2|constructor#_#new#tearOff;
+}
 extension type E(self::B it) implements self::A {
   abstract extension-type-member representation-field get it() → self::B;
   constructor • = self::E|constructor#;
@@ -319,6 +334,11 @@ extension type G<T extends core::Object? = dynamic>(T% o) {
   constructor • = self::G|constructor#;
   constructor tearoff • = self::G|constructor#_#new#tearOff;
 }
+extension type G2<T extends core::Object>(T o) implements core::Object {
+  abstract extension-type-member representation-field get o() → T;
+  constructor • = self::G2|constructor#;
+  constructor tearoff • = self::G2|constructor#_#new#tearOff;
+}
 static extension-type-member method C|constructor#(core::Object? o) → self::C /* = core::Object? */ {
   lowered final self::C /* = core::Object? */ #this = o;
   return #this;
@@ -331,6 +351,12 @@ static extension-type-member method D|constructor#(core::Object o) → self::D /
 }
 static extension-type-member method D|constructor#_#new#tearOff(core::Object o) → self::D /* = core::Object */
   return self::D|constructor#(o);
+static extension-type-member method D2|constructor#(core::Object o) → self::D2 /* = core::Object */ {
+  lowered final self::D2 /* = core::Object */ #this = o;
+  return #this;
+}
+static extension-type-member method D2|constructor#_#new#tearOff(core::Object o) → self::D2 /* = core::Object */
+  return self::D2|constructor#(o);
 static extension-type-member method E|constructor#(self::B it) → self::E /* = self::B */ {
   lowered final self::E /* = self::B */ #this = it;
   return #this;
@@ -349,242 +375,256 @@ static extension-type-member method G|constructor#<T extends core::Object? = dyn
 }
 static extension-type-member method G|constructor#_#new#tearOff<T extends core::Object? = dynamic>(self::G|constructor#_#new#tearOff::T% o) → self::G<self::G|constructor#_#new#tearOff::T%>% /* = self::G|constructor#_#new#tearOff::T% */
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(o);
-static method test<T1 extends core::Object? = dynamic, T2 extends self::A>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2) → dynamic {
+static extension-type-member method G2|constructor#<T extends core::Object>(self::G2|constructor#::T o) → self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ {
+  lowered final self::G2<self::G2|constructor#::T> /* = self::G2|constructor#::T */ #this = o;
+  return #this;
+}
+static extension-type-member method G2|constructor#_#new#tearOff<T extends core::Object>(self::G2|constructor#_#new#tearOff::T o) → self::G2<self::G2|constructor#_#new#tearOff::T> /* = self::G2|constructor#_#new#tearOff::T */
+  return self::G2|constructor#<self::G2|constructor#_#new#tearOff::T>(o);
+static method test<T1 extends core::Object? = dynamic, T2 extends self::A, T3 extends core::Object>(core::Object o, self::A a, self::B b, self::C /* = core::Object? */ c, self::D /* = core::Object */ d, self::D2 /* = core::Object */ d2, self::E /* = self::B */ e, self::F /* = self::B */ f, self::G<self::test::T1%> /* = self::test::T1% */ g1, self::G<self::test::T2> /* = self::test::T2 */ g2, self::G2<self::test::T3> /* = self::test::T3 */ g3) → dynamic {
   o = o;
   o = a;
   o = b;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:33:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:39:7: Error: A value of type 'C' can't be assigned to a variable of type 'Object' because 'C' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = c; // Error
       ^" in c;
   o = d;
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:41:7: Error: A value of type 'D2' can't be assigned to a variable of type 'Object' because 'D2' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = d2; // Error
+      ^" in d2;
   o = e;
   o = f;
-  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:37:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'Object' because 'G<T1>' is nullable and 'Object' isn't.
  - 'Object' is from 'dart:core'.
   o = g1; // Error
       ^" in g1;
-  o = g2;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:40:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
+  o = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:45:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'Object' because 'G<T2>' is nullable and 'Object' isn't.
+ - 'Object' is from 'dart:core'.
+  o = g2; // Error
+      ^" in g2;
+  o = g3;
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'Object' can't be assigned to a variable of type 'A'.
  - 'Object' is from 'dart:core'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = o; // Error
       ^" in o as{TypeError} self::A;
   a = a;
   a = b;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:43:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'C' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = c; // Error
       ^" in c as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:44:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:52:7: Error: A value of type 'D' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = d; // Error
       ^" in d as{TypeError} self::A;
   a = e;
   a = f;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:47:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g1; // Error
       ^" in g1 as{TypeError} self::A;
-  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:48:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
+  a = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:56:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'A'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   a = g2; // Error
       ^" in g2 as{TypeError} self::A;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:50:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'Object' can't be assigned to a variable of type 'B'.
  - 'Object' is from 'dart:core'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = o; // Error
       ^" in o as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:51:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:59:7: Error: A value of type 'A' can't be assigned to a variable of type 'B'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = a; // Error
       ^" in a as{TypeError} self::B;
   b = b;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:53:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'C' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = c; // Error
       ^" in c as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:54:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'D' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = d; // Error
       ^" in d as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:55:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:63:7: Error: A value of type 'E' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = e; // Error
       ^" in e as{TypeError} self::B;
   b = f;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:57:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g1; // Error
       ^" in g1 as{TypeError} self::B;
-  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:58:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
+  b = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'B'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   b = g2; // Error
       ^" in g2 as{TypeError} self::B;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:60:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'Object' can't be assigned to a variable of type 'C'.
  - 'Object' is from 'dart:core'.
   c = o; // Error
       ^" in o as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:61:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:69:7: Error: A value of type 'A' can't be assigned to a variable of type 'C'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = a; // Error
       ^" in a as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:62:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'B' can't be assigned to a variable of type 'C'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   c = b; // Error
       ^" in b as{TypeError} self::C /* = core::Object? */;
   c = c;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:64:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'D' can't be assigned to a variable of type 'C'.
   c = d; // Error
       ^" in d as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:65:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'E' can't be assigned to a variable of type 'C'.
   c = e; // Error
       ^" in e as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:66:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:74:7: Error: A value of type 'F' can't be assigned to a variable of type 'C'.
   c = f; // Error
       ^" in f as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:67:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'C'.
   c = g1; // Error
       ^" in g1 as{TypeError} self::C /* = core::Object? */;
-  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:68:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
+  c = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'C'.
   c = g2; // Error
       ^" in g2 as{TypeError} self::C /* = core::Object? */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:70:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'Object' can't be assigned to a variable of type 'D'.
  - 'Object' is from 'dart:core'.
   d = o; // Error
       ^" in o as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:71:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:79:7: Error: A value of type 'A' can't be assigned to a variable of type 'D'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = a; // Error
       ^" in a as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:72:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'B' can't be assigned to a variable of type 'D'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   d = b; // Error
       ^" in b as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:73:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'C' can't be assigned to a variable of type 'D'.
   d = c; // Error
       ^" in c as{TypeError} self::D /* = core::Object */;
   d = d;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:75:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'E' can't be assigned to a variable of type 'D'.
   d = e; // Error
       ^" in e as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:76:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'F' can't be assigned to a variable of type 'D'.
   d = f; // Error
       ^" in f as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:77:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:85:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'D'.
   d = g1; // Error
       ^" in g1 as{TypeError} self::D /* = core::Object */;
-  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:78:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
+  d = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:86:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'D'.
   d = g2; // Error
       ^" in g2 as{TypeError} self::D /* = core::Object */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:80:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'Object' can't be assigned to a variable of type 'E'.
  - 'Object' is from 'dart:core'.
   e = o; // Error
       ^" in o as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:81:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:89:7: Error: A value of type 'A' can't be assigned to a variable of type 'E'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = a; // Error
       ^" in a as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:82:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'B' can't be assigned to a variable of type 'E'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   e = b; // Error
       ^" in b as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:83:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'C' can't be assigned to a variable of type 'E'.
   e = c; // Error
       ^" in c as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:84:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'D' can't be assigned to a variable of type 'E'.
   e = d; // Error
       ^" in d as{TypeError} self::E /* = self::B */;
   e = e;
   e = f;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:87:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'E'.
   e = g1; // Error
       ^" in g1 as{TypeError} self::E /* = self::B */;
-  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:88:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
+  e = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:96:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'E'.
   e = g2; // Error
       ^" in g2 as{TypeError} self::E /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:90:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'Object' can't be assigned to a variable of type 'F'.
  - 'Object' is from 'dart:core'.
   f = o; // Error
       ^" in o as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:91:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:99:7: Error: A value of type 'A' can't be assigned to a variable of type 'F'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = a; // Error
       ^" in a as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:92:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:7: Error: A value of type 'B' can't be assigned to a variable of type 'F'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   f = b; // Error
       ^" in b as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:93:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:7: Error: A value of type 'C' can't be assigned to a variable of type 'F'.
   f = c; // Error
       ^" in c as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:94:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:7: Error: A value of type 'D' can't be assigned to a variable of type 'F'.
   f = d; // Error
       ^" in d as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:95:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:7: Error: A value of type 'E' can't be assigned to a variable of type 'F'.
   f = e; // Error
       ^" in e as{TypeError} self::F /* = self::B */;
   f = f;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:97:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:7: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'F'.
   f = g1; // Error
       ^" in g1 as{TypeError} self::F /* = self::B */;
-  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:98:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
+  f = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:7: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'F'.
   f = g2; // Error
       ^" in g2 as{TypeError} self::F /* = self::B */;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:100:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T1>'.
  - 'Object' is from 'dart:core'.
   g1 = o; // Error
        ^" in o as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:101:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:109:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T1>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = a; // Error
        ^" in a as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:102:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T1>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g1 = b; // Error
        ^" in b as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:103:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T1>'.
   g1 = c; // Error
        ^" in c as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:104:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T1>'.
   g1 = d; // Error
        ^" in d as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:105:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T1>'.
   g1 = e; // Error
        ^" in e as{TypeError} Never;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:106:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T1>'.
   g1 = f; // Error
        ^" in f as{TypeError} Never;
   g1 = g1;
-  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:108:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
+  g1 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'G<T2>' can't be assigned to a variable of type 'G<T1>'.
   g1 = g2; // Error
        ^" in g2 as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:110:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:118:8: Error: A value of type 'Object' can't be assigned to a variable of type 'G<T2>'.
  - 'Object' is from 'dart:core'.
   g2 = o; // Error
        ^" in o as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:111:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:119:8: Error: A value of type 'A' can't be assigned to a variable of type 'G<T2>'.
  - 'A' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = a; // Error
        ^" in a as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:112:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:120:8: Error: A value of type 'B' can't be assigned to a variable of type 'G<T2>'.
  - 'B' is from 'pkg/front_end/testcases/extension_types/assign_interface_type.dart'.
   g2 = b; // Error
        ^" in b as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:113:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:121:8: Error: A value of type 'C' can't be assigned to a variable of type 'G<T2>'.
   g2 = c; // Error
        ^" in c as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:114:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:122:8: Error: A value of type 'D' can't be assigned to a variable of type 'G<T2>'.
   g2 = d; // Error
        ^" in d as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:115:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:123:8: Error: A value of type 'E' can't be assigned to a variable of type 'G<T2>'.
   g2 = e; // Error
        ^" in e as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:116:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:124:8: Error: A value of type 'F' can't be assigned to a variable of type 'G<T2>'.
   g2 = f; // Error
        ^" in f as{TypeError} Never;
-  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:117:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
+  g2 = invalid-expression "pkg/front_end/testcases/extension_types/assign_interface_type.dart:125:8: Error: A value of type 'G<T1>' can't be assigned to a variable of type 'G<T2>'.
   g2 = g1; // Error
        ^" in g1 as{TypeError} Never;
   g2 = g2;

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.strong.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.strong.transformed.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.weak.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.weak.modular.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.weak.outline.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/cyclic_representation_type.dart.weak.transformed.expect

@@ -10,31 +10,6 @@ library;
 // typedef Alias22a = Alias22b<int>; /* Error */
 //                    ^^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
-// extension type E7(void Function<T extends E7>() it) /* Error */ {}
-//                        ^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E13(Alias13 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
-// typedef Alias13 = void Function<T extends E13>();
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
-// extension type E23(Alias23 it) /* Error */ {}
-//                    ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
-// typedef Alias23<T extends E23> = List<T>;
-//         ^^^^^^^
-//
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
-// extension type E24<T>(Alias24 it) /* Error */ {}
-//                       ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
-// typedef Alias24<T extends E24<T>> = List<T>;
-//         ^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:5:19: Error: An extension type can't depend on itself through its representation type.
 // extension type E1(E1 it) /* Error */ {}
 //                   ^
@@ -95,6 +70,10 @@ library;
 // extension type E6((E6, int) it) /* Error */ {}
 //                   ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:20:24: Error: An extension type can't depend on itself through its representation type.
+// extension type E7(void Function<T extends E7>() it) /* Error */ {}
+//                        ^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:22:22: Error: An extension type can't depend on itself through its representation type.
 // extension type E8<T>(List<E8> it) /* Error */ {}
 //                      ^
@@ -127,6 +106,13 @@ library;
 // typedef Alias12 = void Function(E12);
 //         ^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:37:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E13(Alias13 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:36:9: Context: The issue arises via this type alias.
+// typedef Alias13 = void Function<T extends E13>();
+//         ^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:43:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E15a(Alias15<E15b> it) /* Error */ {}
 //                     ^
@@ -147,19 +133,6 @@ library;
 // typedef Alias15<T> = List<T>;
 //         ^^^^^^^
 //
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
-// extension type E16b(Alias16b<int> it) /* Error */ {}
-//                     ^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
-// extension type E16a(Alias16a<int> it) /* Error */ {}
-//                ^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
-// typedef Alias16b<T> = List<E16a>;
-//         ^^^^^^^^
-// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
-// typedef Alias16a<T> = List<E16b>;
-//         ^^^^^^^^
-//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:21: Error: An extension type can't depend on itself through its representation type.
 // extension type E16a(Alias16a<int> it) /* Error */ {}
 //                     ^
@@ -173,6 +146,19 @@ library;
 // typedef Alias16b<T> = List<E16a>;
 //         ^^^^^^^^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:49:21: Error: An extension type can't depend on itself through its representation type.
+// extension type E16b(Alias16b<int> it) /* Error */ {}
+//                     ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:48:16: Context: The issue arises via this extension type declaration.
+// extension type E16a(Alias16a<int> it) /* Error */ {}
+//                ^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:47:9: Context: The issue arises via this type alias.
+// typedef Alias16b<T> = List<E16a>;
+//         ^^^^^^^^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:46:9: Context: The issue arises via this type alias.
+// typedef Alias16a<T> = List<E16b>;
+//         ^^^^^^^^
+//
 // pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:51:20: Error: An extension type can't depend on itself through its representation type.
 // extension type E17((int, {E17 a}) it) /* Error */ {}
 //                    ^
@@ -191,6 +177,20 @@ library;
 // typedef Alias20 = Alias20; /* Error */
 //         ^
 //
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:71:20: Error: An extension type can't depend on itself through its representation type.
+// extension type E23(Alias23 it) /* Error */ {}
+//                    ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:70:9: Context: The issue arises via this type alias.
+// typedef Alias23<T extends E23> = List<T>;
+//         ^^^^^^^
+//
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:74:23: Error: An extension type can't depend on itself through its representation type.
+// extension type E24<T>(Alias24 it) /* Error */ {}
+//                       ^
+// pkg/front_end/testcases/extension_types/cyclic_representation_type.dart:73:9: Context: The issue arises via this type alias.
+// typedef Alias24<T extends E24<T>> = List<T>;
+//         ^^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.strong.expect

@@ -73,7 +73,7 @@ static extension-type-member method ExtensionType3|constructor#<T extends core::
   lowered final self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */ {
   lowered final self::ExtensionType4 /* = core::int */ #this = it;
@@ -133,5 +133,5 @@ static extension-type-member method ExtensionType7|constructor#id<T extends core
   lowered final self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.strong.transformed.expect

@@ -73,7 +73,7 @@ static extension-type-member method ExtensionType3|constructor#<T extends core::
   lowered final self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */ {
   lowered final self::ExtensionType4 /* = core::int */ #this = it;
@@ -133,5 +133,5 @@ static extension-type-member method ExtensionType7|constructor#id<T extends core
   lowered final self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.weak.expect

@@ -73,7 +73,7 @@ static extension-type-member method ExtensionType3|constructor#<T extends core::
   lowered final self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */ {
   lowered final self::ExtensionType4 /* = core::int */ #this = it;
@@ -133,5 +133,5 @@ static extension-type-member method ExtensionType7|constructor#id<T extends core
   lowered final self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.weak.modular.expect

@@ -73,7 +73,7 @@ static extension-type-member method ExtensionType3|constructor#<T extends core::
   lowered final self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */ {
   lowered final self::ExtensionType4 /* = core::int */ #this = it;
@@ -133,5 +133,5 @@ static extension-type-member method ExtensionType7|constructor#id<T extends core
   lowered final self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.weak.outline.expect

@@ -67,7 +67,7 @@ static extension-type-member method ExtensionType2|constructor#_#new#tearOff(cor
   return self::ExtensionType2|constructor#(it);
 static extension-type-member method ExtensionType3|constructor#<T extends core::num>(self::ExtensionType3|constructor#::T it) → self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */
   ;
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */
   ;
@@ -122,5 +122,5 @@ static extension-type-member method ExtensionType6|constructor#_#id#tearOff(core
   return self::ExtensionType6|constructor#id(it);
 static extension-type-member method ExtensionType7|constructor#id<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */
   ;
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/extension_type_declarations.dart.weak.transformed.expect

@@ -73,7 +73,7 @@ static extension-type-member method ExtensionType3|constructor#<T extends core::
   lowered final self::ExtensionType3<self::ExtensionType3|constructor#::T> /* = self::ExtensionType3|constructor#::T */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T> /* = self::ExtensionType3|constructor#_#new#tearOff::T */
+static extension-type-member method ExtensionType3|constructor#_#new#tearOff<T extends core::num>(self::ExtensionType3|constructor#_#new#tearOff::T it) → self::ExtensionType3<self::ExtensionType3|constructor#_#new#tearOff::T>% /* = self::ExtensionType3|constructor#_#new#tearOff::T */
   return self::ExtensionType3|constructor#<self::ExtensionType3|constructor#_#new#tearOff::T>(it);
 static extension-type-member method ExtensionType4|constructor#(core::int it) → self::ExtensionType4 /* = core::int */ {
   lowered final self::ExtensionType4 /* = core::int */ #this = it;
@@ -133,5 +133,5 @@ static extension-type-member method ExtensionType7|constructor#id<T extends core
   lowered final self::ExtensionType7<self::ExtensionType7|constructor#id::T> /* = core::int */ #this = it;
   return #this;
 }
-static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T> /* = core::int */
+static extension-type-member method ExtensionType7|constructor#_#id#tearOff<T extends core::num>(core::int it) → self::ExtensionType7<self::ExtensionType7|constructor#_#id#tearOff::T>% /* = core::int */
   return self::ExtensionType7|constructor#id<self::ExtensionType7|constructor#_#id#tearOff::T>(it);

pkg/front_end/testcases/extension_types/external.dart.strong.expect

@@ -55,9 +55,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;
@@ -74,7 +74,7 @@ static method method(self::A a) → void {
   a = self::B|method(b1);
   () → self::A f1 = self::B|get#method(b1);
   b2 = self::B|genericMethod<self::B /* = self::A */>(b2, b2);
-  <T extends self::B /* = self::A */>(T) → T f2 = self::B|get#genericMethod(b2);
+  <T extends self::B /* = self::A */>(T%) → T% f2 = self::B|get#genericMethod(b2);
   (core::int) → core::int f3 = self::B|get#genericMethod(b2)<core::int>;
   b1 = self::B|get#getter(b2);
   self::B|set#setter(b1, b2);

pkg/front_end/testcases/extension_types/external.dart.strong.transformed.expect

@@ -55,9 +55,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;
@@ -74,7 +74,7 @@ static method method(self::A a) → void {
   a = self::B|method(b1);
   () → self::A f1 = self::B|get#method(b1);
   b2 = self::B|genericMethod<self::B /* = self::A */>(b2, b2);
-  <T extends self::B /* = self::A */>(T) → T f2 = self::B|get#genericMethod(b2);
+  <T extends self::B /* = self::A */>(T%) → T% f2 = self::B|get#genericMethod(b2);
   (core::int) → core::int f3 = self::B|get#genericMethod(b2)<core::int>;
   b1 = self::B|get#getter(b2);
   self::B|set#setter(b1, b2);

pkg/front_end/testcases/extension_types/external.dart.weak.expect

@@ -55,9 +55,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;
@@ -74,7 +74,7 @@ static method method(self::A a) → void {
   a = self::B|method(b1);
   () → self::A f1 = self::B|get#method(b1);
   b2 = self::B|genericMethod<self::B /* = self::A */>(b2, b2);
-  <T extends self::B /* = self::A */>(T) → T f2 = self::B|get#genericMethod(b2);
+  <T extends self::B /* = self::A */>(T%) → T% f2 = self::B|get#genericMethod(b2);
   (core::int) → core::int f3 = self::B|get#genericMethod(b2)<core::int>;
   b1 = self::B|get#getter(b2);
   self::B|set#setter(b1, b2);

pkg/front_end/testcases/extension_types/external.dart.weak.modular.expect

@@ -55,9 +55,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;
@@ -74,7 +74,7 @@ static method method(self::A a) → void {
   a = self::B|method(b1);
   () → self::A f1 = self::B|get#method(b1);
   b2 = self::B|genericMethod<self::B /* = self::A */>(b2, b2);
-  <T extends self::B /* = self::A */>(T) → T f2 = self::B|get#genericMethod(b2);
+  <T extends self::B /* = self::A */>(T%) → T% f2 = self::B|get#genericMethod(b2);
   (core::int) → core::int f3 = self::B|get#genericMethod(b2)<core::int>;
   b1 = self::B|get#getter(b2);
   self::B|set#setter(b1, b2);

pkg/front_end/testcases/extension_types/external.dart.weak.outline.expect

@@ -44,9 +44,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;

pkg/front_end/testcases/extension_types/external.dart.weak.transformed.expect

@@ -55,9 +55,9 @@ external static extension-type-member method B|set#field(lowered self::A #this,
 external static extension-type-member method B|method(lowered final self::B /* = self::A */ #this) → self::A;
 static extension-type-member method B|get#method(lowered final self::B /* = self::A */ #this) → () → self::A
   return () → self::A => self::B|method(#this);
-external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T t) → self::B|genericMethod::T;
-static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T) → T
-  return <T extends self::B /* = self::A */>(T t) → T => self::B|genericMethod<T>(#this, t);
+external static extension-type-member method B|genericMethod<T extends self::B /* = self::A */>(lowered final self::B /* = self::A */ #this, self::B|genericMethod::T% t) → self::B|genericMethod::T%;
+static extension-type-member method B|get#genericMethod(lowered final self::B /* = self::A */ #this) → <T extends self::B /* = self::A */>(T%) → T%
+  return <T extends self::B /* = self::A */>(T% t) → T% => self::B|genericMethod<T%>(#this, t);
 external static extension-type-member method B|get#getter(lowered final self::B /* = self::A */ #this) → self::B /* = self::A */;
 external static extension-type-member method B|set#setter(lowered final self::B /* = self::A */ #this, self::B /* = self::A */ b) → void;
 external static extension-type-member get B|staticField() → self::A;
@@ -74,7 +74,7 @@ static method method(self::A a) → void {
   a = self::B|method(b1);
   () → self::A f1 = self::B|get#method(b1);
   b2 = self::B|genericMethod<self::B /* = self::A */>(b2, b2);
-  <T extends self::B /* = self::A */>(T) → T f2 = self::B|get#genericMethod(b2);
+  <T extends self::B /* = self::A */>(T%) → T% f2 = self::B|get#genericMethod(b2);
   (core::int) → core::int f3 = self::B|get#genericMethod(b2)<core::int>;
   b1 = self::B|get#getter(b2);
   self::B|set#setter(b1, b2);

pkg/front_end/testcases/extension_types/field_access.dart.strong.expect

@@ -383,7 +383,7 @@ static extension-type-member method FunctionInlineClass|constructor#<T extends c
   lowered final self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */ #this = it;
   return #this;
 }
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void {
   () → self::FunctionInlineClass|test::T% a1 = #this as{Unchecked} () → self::FunctionInlineClass|test::T%;
@@ -409,7 +409,7 @@ Try correcting the name to the name of an existing setter, or defining a setter
   self::FunctionInlineClass|test::T% d3 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
   self::FunctionInlineClass|test::T% d4 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
 }
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ {
   lowered final self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ #this = it;

pkg/front_end/testcases/extension_types/field_access.dart.strong.transformed.expect

@@ -383,7 +383,7 @@ static extension-type-member method FunctionInlineClass|constructor#<T extends c
   lowered final self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */ #this = it;
   return #this;
 }
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void {
   () → self::FunctionInlineClass|test::T% a1 = #this as{Unchecked} () → self::FunctionInlineClass|test::T%;
@@ -409,7 +409,7 @@ Try correcting the name to the name of an existing setter, or defining a setter
   self::FunctionInlineClass|test::T% d3 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
   self::FunctionInlineClass|test::T% d4 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
 }
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ {
   lowered final self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ #this = it;

pkg/front_end/testcases/extension_types/field_access.dart.weak.expect

@@ -383,7 +383,7 @@ static extension-type-member method FunctionInlineClass|constructor#<T extends c
   lowered final self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */ #this = it;
   return #this;
 }
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void {
   () → self::FunctionInlineClass|test::T% a1 = #this as{Unchecked} () → self::FunctionInlineClass|test::T%;
@@ -409,7 +409,7 @@ Try correcting the name to the name of an existing setter, or defining a setter
   self::FunctionInlineClass|test::T% d3 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
   self::FunctionInlineClass|test::T% d4 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
 }
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ {
   lowered final self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ #this = it;

pkg/front_end/testcases/extension_types/field_access.dart.weak.modular.expect

@@ -383,7 +383,7 @@ static extension-type-member method FunctionInlineClass|constructor#<T extends c
   lowered final self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */ #this = it;
   return #this;
 }
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void {
   () → self::FunctionInlineClass|test::T% a1 = #this as{Unchecked} () → self::FunctionInlineClass|test::T%;
@@ -409,7 +409,7 @@ Try correcting the name to the name of an existing setter, or defining a setter
   self::FunctionInlineClass|test::T% d3 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
   self::FunctionInlineClass|test::T% d4 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
 }
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ {
   lowered final self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ #this = it;

pkg/front_end/testcases/extension_types/field_access.dart.weak.outline.expect

@@ -77,11 +77,11 @@ static extension-type-member method GenericInlineClass|get#test<T extends core::
   return (self::GenericInlineClass|get#test::T% t) → void => self::GenericInlineClass|test<self::GenericInlineClass|get#test::T%>(#this, t);
 static extension-type-member method FunctionInlineClass|constructor#<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */
   ;
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void
   ;
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */
   ;

pkg/front_end/testcases/extension_types/field_access.dart.weak.transformed.expect

@@ -383,7 +383,7 @@ static extension-type-member method FunctionInlineClass|constructor#<T extends c
   lowered final self::FunctionInlineClass<self::FunctionInlineClass|constructor#::T%> /* = () → self::FunctionInlineClass|constructor#::T% */ #this = it;
   return #this;
 }
-static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%> /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
+static extension-type-member method FunctionInlineClass|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::FunctionInlineClass|constructor#_#new#tearOff::T% it) → self::FunctionInlineClass<self::FunctionInlineClass|constructor#_#new#tearOff::T%>% /* = () → self::FunctionInlineClass|constructor#_#new#tearOff::T% */
   return self::FunctionInlineClass|constructor#<self::FunctionInlineClass|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method FunctionInlineClass|test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|test::T%> /* = () → self::FunctionInlineClass|test::T% */ #this, () → self::FunctionInlineClass|test::T% t) → void {
   () → self::FunctionInlineClass|test::T% a1 = #this as{Unchecked} () → self::FunctionInlineClass|test::T%;
@@ -409,7 +409,7 @@ Try correcting the name to the name of an existing setter, or defining a setter
   self::FunctionInlineClass|test::T% d3 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
   self::FunctionInlineClass|test::T% d4 = (#this as{Unchecked} () → self::FunctionInlineClass|test::T%)(){() → self::FunctionInlineClass|test::T%};
 }
-static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%> /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
+static extension-type-member method FunctionInlineClass|get#test<T extends core::Object? = dynamic>(lowered final self::FunctionInlineClass<self::FunctionInlineClass|get#test::T%>% /* = () → self::FunctionInlineClass|get#test::T% */ #this) → (() → self::FunctionInlineClass|get#test::T%) → void
   return (() → self::FunctionInlineClass|get#test::T% t) → void => self::FunctionInlineClass|test<self::FunctionInlineClass|get#test::T%>(#this, t);
 static extension-type-member method GenericFunctionInlineClass|constructor#(<T extends core::Object? = dynamic>() → T% it) → self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ {
   lowered final self::GenericFunctionInlineClass /* = <T extends core::Object? = dynamic>() → T% */ #this = it;

pkg/front_end/testcases/extension_types/generic_factory.dart.strong.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/generic_factory.dart.strong.transformed.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/generic_factory.dart.weak.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/generic_factory.dart.weak.modular.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/generic_factory.dart.weak.outline.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/generic_factory.dart.weak.transformed.expect

@@ -15,16 +15,16 @@ static extension-type-member method ET3|constructor#<T extends core::num>(core::
   lowered final self::ET3<self::ET3|constructor#::T> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#new#tearOff<T extends core::num>(core::int id) → self::ET3<self::ET3|constructor#_#new#tearOff::T>% /* = core::int */
   return self::ET3|constructor#<self::ET3|constructor#_#new#tearOff::T>(id);
 static extension-type-member method ET3|constructor#c1<T extends core::num>() → self::ET3<self::ET3|constructor#c1::T> /* = core::int */ {
   lowered final self::ET3<self::ET3|constructor#c1::T> /* = core::int */ #this;
   #this = self::ET3|constructor#<self::ET3|constructor#c1::T>(0);
   return #this;
 }
-static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#c1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#c1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#c1#tearOff::T>();
 static extension-type-member method ET3|constructor#f1<T extends core::num>() → self::ET3<self::ET3|constructor#f1::T> /* = core::int */ /* redirection-target: self::ET3|constructor#c1<self::ET3|constructor#f1::T>*/
   return self::ET3|constructor#c1<self::ET3|constructor#f1::T>();
-static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T> /* = core::int */
+static extension-type-member method ET3|constructor#_#f1#tearOff<T extends core::num>() → self::ET3<self::ET3|constructor#_#f1#tearOff::T>% /* = core::int */
   return self::ET3|constructor#c1<self::ET3|constructor#_#f1#tearOff::T>();

pkg/front_end/testcases/extension_types/inherit_generic.dart.strong.expect

@@ -36,11 +36,11 @@ static extension-type-member method A|constructor#<T extends core::Object? = dyn
   lowered final self::A<self::A|constructor#::T%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   return throw "";
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   return throw "";
@@ -51,11 +51,11 @@ static extension-type-member method B|constructor#<S extends core::Object? = dyn
   lowered final self::B<self::B|constructor#::S%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   return self::A|method<self::B|method2::S%>(#this);
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   return self::A|get#getter<self::B|get#getter2::S%>(#this);

pkg/front_end/testcases/extension_types/inherit_generic.dart.strong.transformed.expect

@@ -36,11 +36,11 @@ static extension-type-member method A|constructor#<T extends core::Object? = dyn
   lowered final self::A<self::A|constructor#::T%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   return throw "";
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   return throw "";
@@ -51,11 +51,11 @@ static extension-type-member method B|constructor#<S extends core::Object? = dyn
   lowered final self::B<self::B|constructor#::S%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   return self::A|method<self::B|method2::S%>(#this);
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   return self::A|get#getter<self::B|get#getter2::S%>(#this);

pkg/front_end/testcases/extension_types/inherit_generic.dart.weak.expect

@@ -36,11 +36,11 @@ static extension-type-member method A|constructor#<T extends core::Object? = dyn
   lowered final self::A<self::A|constructor#::T%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   return throw "";
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   return throw "";
@@ -51,11 +51,11 @@ static extension-type-member method B|constructor#<S extends core::Object? = dyn
   lowered final self::B<self::B|constructor#::S%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   return self::A|method<self::B|method2::S%>(#this);
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   return self::A|get#getter<self::B|get#getter2::S%>(#this);

pkg/front_end/testcases/extension_types/inherit_generic.dart.weak.modular.expect

@@ -36,11 +36,11 @@ static extension-type-member method A|constructor#<T extends core::Object? = dyn
   lowered final self::A<self::A|constructor#::T%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   return throw "";
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   return throw "";
@@ -51,11 +51,11 @@ static extension-type-member method B|constructor#<S extends core::Object? = dyn
   lowered final self::B<self::B|constructor#::S%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   return self::A|method<self::B|method2::S%>(#this);
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   return self::A|get#getter<self::B|get#getter2::S%>(#this);

pkg/front_end/testcases/extension_types/inherit_generic.dart.weak.outline.expect

@@ -34,11 +34,11 @@ extension type C(core::Object i) implements self::A<core::int> /* = core::Object
 }
 static extension-type-member method A|constructor#<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#::T%> /* = core::Object */
   ;
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   ;
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   ;
@@ -48,11 +48,11 @@ static extension-type-member method A|[]<T extends core::Object? = dynamic>(lowe
   ;
 static extension-type-member method B|constructor#<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#::S%> /* = core::Object */
   ;
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   ;
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   ;

pkg/front_end/testcases/extension_types/inherit_generic.dart.weak.transformed.expect

@@ -36,11 +36,11 @@ static extension-type-member method A|constructor#<T extends core::Object? = dyn
   lowered final self::A<self::A|constructor#::T%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%> /* = core::Object */
+static extension-type-member method A|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::Object it) → self::A<self::A|constructor#_#new#tearOff::T%>% /* = core::Object */
   return self::A|constructor#<self::A|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method A|method<T extends core::Object? = dynamic>(lowered final self::A<self::A|method::T%> /* = core::Object */ #this) → self::A|method::T%
   return throw "";
-static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%> /* = core::Object */ #this) → () → self::A|get#method::T%
+static extension-type-member method A|get#method<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#method::T%>% /* = core::Object */ #this) → () → self::A|get#method::T%
   return () → self::A|get#method::T% => self::A|method<self::A|get#method::T%>(#this);
 static extension-type-member method A|get#getter<T extends core::Object? = dynamic>(lowered final self::A<self::A|get#getter::T%> /* = core::Object */ #this) → self::A|get#getter::T%
   return throw "";
@@ -51,11 +51,11 @@ static extension-type-member method B|constructor#<S extends core::Object? = dyn
   lowered final self::B<self::B|constructor#::S%> /* = core::Object */ #this = it;
   return #this;
 }
-static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%> /* = core::Object */
+static extension-type-member method B|constructor#_#new#tearOff<S extends core::Object? = dynamic>(core::Object it) → self::B<self::B|constructor#_#new#tearOff::S%>% /* = core::Object */
   return self::B|constructor#<self::B|constructor#_#new#tearOff::S%>(it);
 static extension-type-member method B|method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|method2::S%> /* = core::Object */ #this) → self::B|method2::S%
   return self::A|method<self::B|method2::S%>(#this);
-static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%> /* = core::Object */ #this) → () → self::B|get#method2::S%
+static extension-type-member method B|get#method2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#method2::S%>% /* = core::Object */ #this) → () → self::B|get#method2::S%
   return () → self::B|get#method2::S% => self::B|method2<self::B|get#method2::S%>(#this);
 static extension-type-member method B|get#getter2<S extends core::Object? = dynamic>(lowered final self::B<self::B|get#getter2::S%> /* = core::Object */ #this) → self::B|get#getter2::S%
   return self::A|get#getter<self::B|get#getter2::S%>(#this);

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.strong.expect

@@ -87,7 +87,7 @@ static extension-type-member method H|constructor#<T extends core::Object? = dyn
   lowered final self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */ #this = h;
   return #this;
 }
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic {
   self::A /* = core::int */ a = self::A|constructor#(42);

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.strong.transformed.expect

@@ -87,7 +87,7 @@ static extension-type-member method H|constructor#<T extends core::Object? = dyn
   lowered final self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */ #this = h;
   return #this;
 }
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic {
   self::A /* = core::int */ a = self::A|constructor#(42);

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.weak.expect

@@ -87,7 +87,7 @@ static extension-type-member method H|constructor#<T extends core::Object? = dyn
   lowered final self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */ #this = h;
   return #this;
 }
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic {
   self::A /* = core::int */ a = self::A|constructor#(42);

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.weak.modular.expect

@@ -87,7 +87,7 @@ static extension-type-member method H|constructor#<T extends core::Object? = dyn
   lowered final self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */ #this = h;
   return #this;
 }
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic {
   self::A /* = core::int */ a = self::A|constructor#(42);

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.weak.outline.expect

@@ -74,7 +74,7 @@ static extension-type-member method G|constructor#_#new#tearOff<T extends core::
   return self::G|constructor#<self::G|constructor#_#new#tearOff::T%>(g);
 static extension-type-member method H|constructor#<T extends core::Object? = dynamic>(core::List<self::H|constructor#::T%> h) → self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */
   ;
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic
   ;

pkg/front_end/testcases/extension_types/inherited_representation_field.dart.weak.transformed.expect

@@ -87,7 +87,7 @@ static extension-type-member method H|constructor#<T extends core::Object? = dyn
   lowered final self::H<self::H|constructor#::T%> /* = core::List<self::H|constructor#::T%> */ #this = h;
   return #this;
 }
-static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%> /* = core::List<self::H|constructor#_#new#tearOff::T%> */
+static extension-type-member method H|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::H|constructor#_#new#tearOff::T%> h) → self::H<self::H|constructor#_#new#tearOff::T%>% /* = core::List<self::H|constructor#_#new#tearOff::T%> */
   return self::H|constructor#<self::H|constructor#_#new#tearOff::T%>(h);
 static method main() → dynamic {
   self::A /* = core::int */ a = self::A|constructor#(42);

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.strong.expect

@@ -24,6 +24,6 @@ static extension-type-member method Class3|constructor#<T extends core::Object?
   lowered final self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */ #this = it;
   return #this;
 }
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic {}

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.strong.transformed.expect

@@ -24,6 +24,6 @@ static extension-type-member method Class3|constructor#<T extends core::Object?
   lowered final self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */ #this = it;
   return #this;
 }
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic {}

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.weak.expect

@@ -24,6 +24,6 @@ static extension-type-member method Class3|constructor#<T extends core::Object?
   lowered final self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */ #this = it;
   return #this;
 }
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic {}

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.weak.modular.expect

@@ -24,6 +24,6 @@ static extension-type-member method Class3|constructor#<T extends core::Object?
   lowered final self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */ #this = it;
   return #this;
 }
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic {}

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.weak.outline.expect

@@ -20,7 +20,7 @@ static extension-type-member method Class1|constructor#_#new#tearOff(core::int i
   return self::Class1|constructor#(it);
 static extension-type-member method Class3|constructor#<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#::T%> it) → self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */
   ;
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic
   ;

pkg/front_end/testcases/extension_types/inline_class_declaration.dart.weak.transformed.expect

@@ -24,6 +24,6 @@ static extension-type-member method Class3|constructor#<T extends core::Object?
   lowered final self::Class3<self::Class3|constructor#::T%> /* = core::List<self::Class3|constructor#::T%> */ #this = it;
   return #this;
 }
-static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%> /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
+static extension-type-member method Class3|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::List<self::Class3|constructor#_#new#tearOff::T%> it) → self::Class3<self::Class3|constructor#_#new#tearOff::T%>% /* = core::List<self::Class3|constructor#_#new#tearOff::T%> */
   return self::Class3|constructor#<self::Class3|constructor#_#new#tearOff::T%>(it);
 static method method(self::Class1 /* = core::int */ c1, self::Class3<core::int> /* = core::List<core::int> */ c3) → dynamic {}

pkg/front_end/testcases/extension_types/issue52595.dart.strong.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = #C1;
+static const field self::V<core::int>% /* = core::int */ c = #C1;
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 constants  {

pkg/front_end/testcases/extension_types/issue52595.dart.strong.transformed.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = #C1;
+static const field self::V<core::int>% /* = core::int */ c = #C1;
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 constants  {

pkg/front_end/testcases/extension_types/issue52595.dart.weak.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = #C1;
+static const field self::V<core::int>% /* = core::int */ c = #C1;
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 constants  {

pkg/front_end/testcases/extension_types/issue52595.dart.weak.modular.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = #C1;
+static const field self::V<core::int>% /* = core::int */ c = #C1;
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 constants  {

pkg/front_end/testcases/extension_types/issue52595.dart.weak.outline.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = const self::V|constructor#<core::int>(0);
+static const field self::V<core::int>% /* = core::int */ c = const self::V|constructor#<core::int>(0);
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 

pkg/front_end/testcases/extension_types/issue52595.dart.weak.transformed.expect

@@ -7,12 +7,12 @@ extension type V<T extends core::Object? = dynamic>(core::int id) {
   constructor • = self::V|constructor#;
   constructor tearoff • = self::V|constructor#_#new#tearOff;
 }
-static const field self::V<core::int> /* = core::int */ c = #C1;
+static const field self::V<core::int>% /* = core::int */ c = #C1;
 static extension-type-member method V|constructor#<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#::T%> /* = core::int */ {
   lowered final self::V<self::V|constructor#::T%> /* = core::int */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%> /* = core::int */
+static extension-type-member method V|constructor#_#new#tearOff<T extends core::Object? = dynamic>(core::int id) → self::V<self::V|constructor#_#new#tearOff::T%>% /* = core::int */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::T%>(id);
 
 constants  {

pkg/front_end/testcases/extension_types/issue53155.dart.strong.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f = #C2;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     : super core::Object::•()
     ;
 }
@@ -19,16 +19,16 @@ static extension-type-member method V|constructor#<X1 extends core::num, X2 exte
   lowered final self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   return t as self::V<core::int, core::int> /* = core::int */;
 static method main() → dynamic {
-  self::V<core::int, core::num> /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
+  self::V<core::int, core::num>% /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
   self::expect(42, v as{Unchecked} core::int);
-  self::expect(v, self::foo<self::V<core::int, core::num> /* = core::int */>(v));
-  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int> /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
-  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int> /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(v, self::foo<self::V<core::int, core::num>% /* = core::int */>(v));
+  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
 }
 static method expect(dynamic expected, dynamic actual) → dynamic {
   if(!(expected =={core::Object::==}{(core::Object) → core::bool} actual))

pkg/front_end/testcases/extension_types/issue53155.dart.strong.transformed.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f = #C2;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     : super core::Object::•()
     ;
 }
@@ -19,16 +19,16 @@ static extension-type-member method V|constructor#<X1 extends core::num, X2 exte
   lowered final self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   return t as self::V<core::int, core::int> /* = core::int */;
 static method main() → dynamic {
-  self::V<core::int, core::num> /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
+  self::V<core::int, core::num>% /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
   self::expect(42, v as{Unchecked} core::int);
-  self::expect(v, self::foo<self::V<core::int, core::num> /* = core::int */>(v));
-  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int> /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
-  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int> /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(v, self::foo<self::V<core::int, core::num>% /* = core::int */>(v));
+  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
 }
 static method expect(dynamic expected, dynamic actual) → dynamic {
   if(!(expected =={core::Object::==}{(core::Object) → core::bool} actual))

pkg/front_end/testcases/extension_types/issue53155.dart.weak.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f = #C2;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     : super core::Object::•()
     ;
 }
@@ -19,16 +19,16 @@ static extension-type-member method V|constructor#<X1 extends core::num, X2 exte
   lowered final self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   return t as self::V<core::int, core::int> /* = core::int */;
 static method main() → dynamic {
-  self::V<core::int, core::num> /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
+  self::V<core::int, core::num>% /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
   self::expect(42, v as{Unchecked} core::int);
-  self::expect(v, self::foo<self::V<core::int, core::num> /* = core::int */>(v));
-  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int> /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
-  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int> /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(v, self::foo<self::V<core::int, core::num>% /* = core::int */>(v));
+  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
 }
 static method expect(dynamic expected, dynamic actual) → dynamic {
   if(!(expected =={core::Object::==}{(core::Object) → core::bool} actual))

pkg/front_end/testcases/extension_types/issue53155.dart.weak.modular.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f = #C2;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     : super core::Object::•()
     ;
 }
@@ -19,16 +19,16 @@ static extension-type-member method V|constructor#<X1 extends core::num, X2 exte
   lowered final self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   return t as self::V<core::int, core::int> /* = core::int */;
 static method main() → dynamic {
-  self::V<core::int, core::num> /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
+  self::V<core::int, core::num>% /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
   self::expect(42, v as{Unchecked} core::int);
-  self::expect(v, self::foo<self::V<core::int, core::num> /* = core::int */>(v));
-  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int> /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
-  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int> /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(v, self::foo<self::V<core::int, core::num>% /* = core::int */>(v));
+  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
 }
 static method expect(dynamic expected, dynamic actual) → dynamic {
   if(!(expected =={core::Object::==}{(core::Object) → core::bool} actual))

pkg/front_end/testcases/extension_types/issue53155.dart.weak.outline.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     ;
 }
 extension type V<X1 extends core::num, X2 extends core::Object>(X1 id) {
@@ -16,9 +16,9 @@ extension type V<X1 extends core::num, X2 extends core::Object>(X1 id) {
 }
 static extension-type-member method V|constructor#<X1 extends core::num, X2 extends core::Object>(self::V|constructor#::X1 id) → self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */
   ;
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   ;
 static method main() → dynamic
   ;

pkg/front_end/testcases/extension_types/issue53155.dart.weak.transformed.expect

@@ -6,7 +6,7 @@ typedef Foo<unrelated T extends self::V<core::num, core::Object> /* = core::num
 typedef IntNumV = self::V<core::int, core::num> /* = core::int */;
 class C<T extends self::V<core::num, core::Object> /* = core::num */> extends core::Object {
   field (self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */ f = #C2;
-  synthetic constructor •() → self::C<self::C::T>
+  synthetic constructor •() → self::C<self::C::T%>
     : super core::Object::•()
     ;
 }
@@ -19,16 +19,16 @@ static extension-type-member method V|constructor#<X1 extends core::num, X2 exte
   lowered final self::V<self::V|constructor#::X1, self::V|constructor#::X2> /* = self::V|constructor#::X1 */ #this = id;
   return #this;
 }
-static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2> /* = self::V|constructor#_#new#tearOff::X1 */
+static extension-type-member method V|constructor#_#new#tearOff<X1 extends core::num, X2 extends core::Object>(self::V|constructor#_#new#tearOff::X1 id) → self::V<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>% /* = self::V|constructor#_#new#tearOff::X1 */
   return self::V|constructor#<self::V|constructor#_#new#tearOff::X1, self::V|constructor#_#new#tearOff::X2>(id);
-static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T t) → self::V<core::int, core::int> /* = core::int */
+static method foo<T extends self::V<core::num, core::Object> /* = core::num */>(self::foo::T% t) → self::V<core::int, core::int> /* = core::int */
   return t as self::V<core::int, core::int> /* = core::int */;
 static method main() → dynamic {
-  self::V<core::int, core::num> /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
+  self::V<core::int, core::num>% /* = core::int */ v = self::V|constructor#<core::int, core::num>(42);
   self::expect(42, v as{Unchecked} core::int);
-  self::expect(v, self::foo<self::V<core::int, core::num> /* = core::int */>(v));
-  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int> /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
-  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int> /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int> /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(v, self::foo<self::V<core::int, core::num>% /* = core::int */>(v));
+  self::expect(self::V|constructor#<core::int, core::int>(0), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t1 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t2 = self::V|constructor#<core::int, core::int>(0) in #t1.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t2){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
+  self::expect(self::V|constructor#<core::int, core::Object>(1), let final self::C<self::V<core::int, core::int>% /* = core::int */> #t3 = new self::C::•<self::V<core::int, core::int> /* = core::int */>() in let final self::V<core::int, core::int>% /* = core::int */ #t4 = self::V|constructor#<core::int, core::int>(1) in #t3.{self::C::f}{(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */}(#t4){(self::V<core::int, core::int> /* = core::int */) → self::V<core::int, core::int> /* = core::int */});
 }
 static method expect(dynamic expected, dynamic actual) → dynamic {
   if(!(expected =={core::Object::==}{(core::Object) → core::bool} actual))

pkg/front_end/testcases/extension_types/issue53207.dart.strong.expect

@@ -87,7 +87,7 @@ static extension-type-member method E2|constructor#<X extends asy::Future<core::
   lowered final self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/ {
   lowered final self::E3 /* = FutureOr<core::bool>*/ #this = foo;
@@ -99,7 +99,7 @@ static extension-type-member method E4|constructor#<X extends FutureOr<core::dou
   lowered final self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ {
   lowered final self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ #this = foo;

pkg/front_end/testcases/extension_types/issue53207.dart.strong.transformed.expect

@@ -87,7 +87,7 @@ static extension-type-member method E2|constructor#<X extends asy::Future<core::
   lowered final self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/ {
   lowered final self::E3 /* = FutureOr<core::bool>*/ #this = foo;
@@ -99,7 +99,7 @@ static extension-type-member method E4|constructor#<X extends FutureOr<core::dou
   lowered final self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ {
   lowered final self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ #this = foo;

pkg/front_end/testcases/extension_types/issue53207.dart.weak.expect

@@ -87,7 +87,7 @@ static extension-type-member method E2|constructor#<X extends asy::Future<core::
   lowered final self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/ {
   lowered final self::E3 /* = FutureOr<core::bool>*/ #this = foo;
@@ -99,7 +99,7 @@ static extension-type-member method E4|constructor#<X extends FutureOr<core::dou
   lowered final self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ {
   lowered final self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ #this = foo;

pkg/front_end/testcases/extension_types/issue53207.dart.weak.modular.expect

@@ -87,7 +87,7 @@ static extension-type-member method E2|constructor#<X extends asy::Future<core::
   lowered final self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/ {
   lowered final self::E3 /* = FutureOr<core::bool>*/ #this = foo;
@@ -99,7 +99,7 @@ static extension-type-member method E4|constructor#<X extends FutureOr<core::dou
   lowered final self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ {
   lowered final self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ #this = foo;

pkg/front_end/testcases/extension_types/issue53207.dart.weak.outline.expect

@@ -56,7 +56,7 @@ static extension-type-member method E1|constructor#_#new#tearOff(asy::Future<cor
   return self::E1|constructor#(foo);
 static extension-type-member method E2|constructor#<X extends asy::Future<core::String>>(self::E2|constructor#::X foo) → self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */
   ;
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/
   ;
@@ -64,7 +64,7 @@ static extension-type-member method E3|constructor#_#new#tearOff(FutureOr<core::
   return self::E3|constructor#(foo);
 static extension-type-member method E4|constructor#<X extends FutureOr<core::double>>(self::E4|constructor#::X foo) → self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */
   ;
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */
   ;

pkg/front_end/testcases/extension_types/issue53207.dart.weak.transformed.expect

@@ -87,7 +87,7 @@ static extension-type-member method E2|constructor#<X extends asy::Future<core::
   lowered final self::E2<self::E2|constructor#::X> /* = self::E2|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X> /* = self::E2|constructor#_#new#tearOff::X */
+static extension-type-member method E2|constructor#_#new#tearOff<X extends asy::Future<core::String>>(self::E2|constructor#_#new#tearOff::X foo) → self::E2<self::E2|constructor#_#new#tearOff::X>% /* = self::E2|constructor#_#new#tearOff::X */
   return self::E2|constructor#<self::E2|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E3|constructor#(FutureOr<core::bool>foo) → self::E3 /* = FutureOr<core::bool>*/ {
   lowered final self::E3 /* = FutureOr<core::bool>*/ #this = foo;
@@ -99,7 +99,7 @@ static extension-type-member method E4|constructor#<X extends FutureOr<core::dou
   lowered final self::E4<self::E4|constructor#::X> /* = self::E4|constructor#::X */ #this = foo;
   return #this;
 }
-static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X> /* = self::E4|constructor#_#new#tearOff::X */
+static extension-type-member method E4|constructor#_#new#tearOff<X extends FutureOr<core::double>>(self::E4|constructor#_#new#tearOff::X foo) → self::E4<self::E4|constructor#_#new#tearOff::X>% /* = self::E4|constructor#_#new#tearOff::X */
   return self::E4|constructor#<self::E4|constructor#_#new#tearOff::X>(foo);
 static extension-type-member method E5|constructor#<X extends core::Object? = dynamic>(self::E5|constructor#::X% foo) → self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ {
   lowered final self::E5<self::E5|constructor#::X%> /* = self::E5|constructor#::X% */ #this = foo;

pkg/front_end/testcases/extension_types/issue53780.dart.strong.expect

@@ -12,7 +12,7 @@ static extension-type-member method E|constructor#<T extends core::Object? = dyn
   lowered final self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */ #this = it;
   return #this;
 }
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   return (#this as{Unchecked} ({required t: self::E|get#t::T%})).t{self::E|get#t::T%};

pkg/front_end/testcases/extension_types/issue53780.dart.strong.transformed.expect

@@ -12,7 +12,7 @@ static extension-type-member method E|constructor#<T extends core::Object? = dyn
   lowered final self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */ #this = it;
   return #this;
 }
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   return (#this as{Unchecked} ({required t: self::E|get#t::T%})).t{self::E|get#t::T%};

pkg/front_end/testcases/extension_types/issue53780.dart.weak.expect

@@ -13,7 +13,7 @@ static extension-type-member method E|constructor#<T extends core::Object? = dyn
   lowered final self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */ #this = it;
   return #this;
 }
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   return (#this as{Unchecked} ({required t: self::E|get#t::T%})).t{self::E|get#t::T%};

pkg/front_end/testcases/extension_types/issue53780.dart.weak.modular.expect

@@ -13,7 +13,7 @@ static extension-type-member method E|constructor#<T extends core::Object? = dyn
   lowered final self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */ #this = it;
   return #this;
 }
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   return (#this as{Unchecked} ({required t: self::E|get#t::T%})).t{self::E|get#t::T%};

pkg/front_end/testcases/extension_types/issue53780.dart.weak.outline.expect

@@ -10,7 +10,7 @@ extension type E<T extends core::Object? = dynamic>(({required t: T%}) it) {
 }
 static extension-type-member method E|constructor#<T extends core::Object? = dynamic>(({required t: self::E|constructor#::T%}) it) → self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */
   ;
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   ;

pkg/front_end/testcases/extension_types/issue53780.dart.weak.transformed.expect

@@ -13,7 +13,7 @@ static extension-type-member method E|constructor#<T extends core::Object? = dyn
   lowered final self::E<self::E|constructor#::T%> /* =({required t: self::E|constructor#::T%}) */ #this = it;
   return #this;
 }
-static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%> /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
+static extension-type-member method E|constructor#_#new#tearOff<T extends core::Object? = dynamic>(({required t: self::E|constructor#_#new#tearOff::T%}) it) → self::E<self::E|constructor#_#new#tearOff::T%>% /* =({required t: self::E|constructor#_#new#tearOff::T%}) */
   return self::E|constructor#<self::E|constructor#_#new#tearOff::T%>(it);
 static extension-type-member method E|get#t<T extends core::Object? = dynamic>(lowered final self::E<self::E|get#t::T%> /* =({required t: self::E|get#t::T%}) */ #this) → self::E|get#t::T%
   return (#this as{Unchecked} ({required t: self::E|get#t::T%})).t{self::E|get#t::T%};

pkg/front_end/testcases/extension_types/non_covariant_type_parameter.dart.strong.expect

@@ -113,71 +113,71 @@ static extension-type-member method ET_Contravariant|constructor#<T extends core
   lowered final self::ET_Contravariant<self::ET_Contravariant|constructor#::T%> /* = (self::ET_Contravariant|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Contravariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Contravariant|constructor#_#new#tearOff::T%) → void f) → self::ET_Contravariant<self::ET_Contravariant|constructor#_#new#tearOff::T%> /* = (self::ET_Contravariant|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_Contravariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Contravariant|constructor#_#new#tearOff::T%) → void f) → self::ET_Contravariant<self::ET_Contravariant|constructor#_#new#tearOff::T%>% /* = (self::ET_Contravariant|constructor#_#new#tearOff::T%) → void */
   return self::ET_Contravariant|constructor#<self::ET_Contravariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Invariant|constructor#<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#::T%> /* = <S extends self::ET_Invariant|constructor#::T% = dynamic>() → void */ {
   lowered final self::ET_Invariant<self::ET_Invariant|constructor#::T%> /* = <S extends self::ET_Invariant|constructor#::T% = dynamic>() → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Invariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#_#new#tearOff::T%> /* = <S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void */
+static extension-type-member method ET_Invariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#_#new#tearOff::T%>% /* = <S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void */
   return self::ET_Invariant|constructor#<self::ET_Invariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Covariant|constructor#<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#::T%> /* = () → self::ET_Covariant|constructor#::T% */ {
   lowered final self::ET_Covariant<self::ET_Covariant|constructor#::T%> /* = () → self::ET_Covariant|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Covariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#_#new#tearOff::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#_#new#tearOff::T%> /* = () → self::ET_Covariant|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_Covariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#_#new#tearOff::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#_#new#tearOff::T%>% /* = () → self::ET_Covariant|constructor#_#new#tearOff::T% */
   return self::ET_Covariant|constructor#<self::ET_Covariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Bivariant|constructor#<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#::T%> /* = (self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% */ {
   lowered final self::ET_Bivariant<self::ET_Bivariant|constructor#::T%> /* = (self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Bivariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#_#new#tearOff::T%> /* = (self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_Bivariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#_#new#tearOff::T%>% /* = (self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% */
   return self::ET_Bivariant|constructor#<self::ET_Bivariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias|constructor#<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#::T%> /* = (self::ET_ContravariantAlias|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#::T%> /* = (self::ET_ContravariantAlias|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%> /* = (self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%>% /* = (self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias|constructor#<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_InvariantAlias|constructor#<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#::T%> /* = <S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void */ {
   lowered final self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#::T%> /* = <S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_InvariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#_#new#tearOff::T%> /* = <S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void */
+static extension-type-member method ET_InvariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#_#new#tearOff::T%>% /* = <S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void */
   return self::ET_InvariantAlias|constructor#<self::ET_InvariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias|constructor#<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#::T%> /* = () → self::ET_CovariantAlias|constructor#::T% */ {
   lowered final self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#::T%> /* = () → self::ET_CovariantAlias|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#_#new#tearOff::T%> /* = () → self::ET_CovariantAlias|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_CovariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#_#new#tearOff::T%>% /* = () → self::ET_CovariantAlias|constructor#_#new#tearOff::T% */
   return self::ET_CovariantAlias|constructor#<self::ET_CovariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_BivariantAlias|constructor#<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#::T%> /* = (self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% */ {
   lowered final self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#::T%> /* = (self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_BivariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#_#new#tearOff::T%> /* = (self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_BivariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#_#new#tearOff::T%>% /* = (self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% */
   return self::ET_BivariantAlias|constructor#<self::ET_BivariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias1|constructor#<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#::T%> /* = () → (self::ET_ContravariantAlias1|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#::T%> /* = () → (self::ET_ContravariantAlias1|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%> /* = () → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%>% /* = () → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias1|constructor#<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias2|constructor#<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#::T%> /* = (() → self::ET_ContravariantAlias2|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#::T%> /* = (() → self::ET_ContravariantAlias2|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%> /* = (() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%>% /* = (() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias2|constructor#<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias1|constructor#<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#::T%> /* = () → () → self::ET_CovariantAlias1|constructor#::T% */ {
   lowered final self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#::T%> /* = () → () → self::ET_CovariantAlias1|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%> /* = () → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_CovariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%>% /* = () → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% */
   return self::ET_CovariantAlias1|constructor#<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias2|constructor#<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#::T%> /* = ((self::ET_CovariantAlias2|constructor#::T%) → void) → void */ {
   lowered final self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#::T%> /* = ((self::ET_CovariantAlias2|constructor#::T%) → void) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%> /* = ((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void */
+static extension-type-member method ET_CovariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%>% /* = ((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void */
   return self::ET_CovariantAlias2|constructor#<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%>(f);

pkg/front_end/testcases/extension_types/non_covariant_type_parameter.dart.strong.transformed.expect

@@ -113,71 +113,71 @@ static extension-type-member method ET_Contravariant|constructor#<T extends core
   lowered final self::ET_Contravariant<self::ET_Contravariant|constructor#::T%> /* = (self::ET_Contravariant|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Contravariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Contravariant|constructor#_#new#tearOff::T%) → void f) → self::ET_Contravariant<self::ET_Contravariant|constructor#_#new#tearOff::T%> /* = (self::ET_Contravariant|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_Contravariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Contravariant|constructor#_#new#tearOff::T%) → void f) → self::ET_Contravariant<self::ET_Contravariant|constructor#_#new#tearOff::T%>% /* = (self::ET_Contravariant|constructor#_#new#tearOff::T%) → void */
   return self::ET_Contravariant|constructor#<self::ET_Contravariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Invariant|constructor#<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#::T%> /* = <S extends self::ET_Invariant|constructor#::T% = dynamic>() → void */ {
   lowered final self::ET_Invariant<self::ET_Invariant|constructor#::T%> /* = <S extends self::ET_Invariant|constructor#::T% = dynamic>() → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Invariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#_#new#tearOff::T%> /* = <S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void */
+static extension-type-member method ET_Invariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_Invariant<self::ET_Invariant|constructor#_#new#tearOff::T%>% /* = <S extends self::ET_Invariant|constructor#_#new#tearOff::T% = dynamic>() → void */
   return self::ET_Invariant|constructor#<self::ET_Invariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Covariant|constructor#<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#::T%> /* = () → self::ET_Covariant|constructor#::T% */ {
   lowered final self::ET_Covariant<self::ET_Covariant|constructor#::T%> /* = () → self::ET_Covariant|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Covariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#_#new#tearOff::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#_#new#tearOff::T%> /* = () → self::ET_Covariant|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_Covariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_Covariant|constructor#_#new#tearOff::T% f) → self::ET_Covariant<self::ET_Covariant|constructor#_#new#tearOff::T%>% /* = () → self::ET_Covariant|constructor#_#new#tearOff::T% */
   return self::ET_Covariant|constructor#<self::ET_Covariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_Bivariant|constructor#<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#::T%> /* = (self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% */ {
   lowered final self::ET_Bivariant<self::ET_Bivariant|constructor#::T%> /* = (self::ET_Bivariant|constructor#::T%) → self::ET_Bivariant|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_Bivariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#_#new#tearOff::T%> /* = (self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_Bivariant|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% f) → self::ET_Bivariant<self::ET_Bivariant|constructor#_#new#tearOff::T%>% /* = (self::ET_Bivariant|constructor#_#new#tearOff::T%) → self::ET_Bivariant|constructor#_#new#tearOff::T% */
   return self::ET_Bivariant|constructor#<self::ET_Bivariant|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias|constructor#<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#::T%> /* = (self::ET_ContravariantAlias|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#::T%> /* = (self::ET_ContravariantAlias|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%> /* = (self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%>% /* = (self::ET_ContravariantAlias|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias|constructor#<self::ET_ContravariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_InvariantAlias|constructor#<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#::T%> /* = <S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void */ {
   lowered final self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#::T%> /* = <S extends self::ET_InvariantAlias|constructor#::T% = dynamic>() → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_InvariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#_#new#tearOff::T%> /* = <S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void */
+static extension-type-member method ET_InvariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(<S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void f) → self::ET_InvariantAlias<self::ET_InvariantAlias|constructor#_#new#tearOff::T%>% /* = <S extends self::ET_InvariantAlias|constructor#_#new#tearOff::T% = dynamic>() → void */
   return self::ET_InvariantAlias|constructor#<self::ET_InvariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias|constructor#<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#::T%> /* = () → self::ET_CovariantAlias|constructor#::T% */ {
   lowered final self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#::T%> /* = () → self::ET_CovariantAlias|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#_#new#tearOff::T%> /* = () → self::ET_CovariantAlias|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_CovariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → self::ET_CovariantAlias|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias<self::ET_CovariantAlias|constructor#_#new#tearOff::T%>% /* = () → self::ET_CovariantAlias|constructor#_#new#tearOff::T% */
   return self::ET_CovariantAlias|constructor#<self::ET_CovariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_BivariantAlias|constructor#<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#::T%> /* = (self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% */ {
   lowered final self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#::T%> /* = (self::ET_BivariantAlias|constructor#::T%) → self::ET_BivariantAlias|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_BivariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#_#new#tearOff::T%> /* = (self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_BivariantAlias|constructor#_#new#tearOff<T extends core::Object? = dynamic>((self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% f) → self::ET_BivariantAlias<self::ET_BivariantAlias|constructor#_#new#tearOff::T%>% /* = (self::ET_BivariantAlias|constructor#_#new#tearOff::T%) → self::ET_BivariantAlias|constructor#_#new#tearOff::T% */
   return self::ET_BivariantAlias|constructor#<self::ET_BivariantAlias|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias1|constructor#<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#::T%> /* = () → (self::ET_ContravariantAlias1|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#::T%> /* = () → (self::ET_ContravariantAlias1|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%> /* = () → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias1<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%>% /* = () → (self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias1|constructor#<self::ET_ContravariantAlias1|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_ContravariantAlias2|constructor#<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#::T%> /* = (() → self::ET_ContravariantAlias2|constructor#::T%) → void */ {
   lowered final self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#::T%> /* = (() → self::ET_ContravariantAlias2|constructor#::T%) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_ContravariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%> /* = (() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void */
+static extension-type-member method ET_ContravariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>((() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void f) → self::ET_ContravariantAlias2<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%>% /* = (() → self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%) → void */
   return self::ET_ContravariantAlias2|constructor#<self::ET_ContravariantAlias2|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias1|constructor#<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#::T%> /* = () → () → self::ET_CovariantAlias1|constructor#::T% */ {
   lowered final self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#::T%> /* = () → () → self::ET_CovariantAlias1|constructor#::T% */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%> /* = () → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% */
+static extension-type-member method ET_CovariantAlias1|constructor#_#new#tearOff<T extends core::Object? = dynamic>(() → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% f) → self::ET_CovariantAlias1<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%>% /* = () → () → self::ET_CovariantAlias1|constructor#_#new#tearOff::T% */
   return self::ET_CovariantAlias1|constructor#<self::ET_CovariantAlias1|constructor#_#new#tearOff::T%>(f);
 static extension-type-member method ET_CovariantAlias2|constructor#<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#::T%> /* = ((self::ET_CovariantAlias2|constructor#::T%) → void) → void */ {
   lowered final self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#::T%> /* = ((self::ET_CovariantAlias2|constructor#::T%) → void) → void */ #this = f;
   return #this;
 }
-static extension-type-member method ET_CovariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%> /* = ((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void */
+static extension-type-member method ET_CovariantAlias2|constructor#_#new#tearOff<T extends core::Object? = dynamic>(((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void f) → self::ET_CovariantAlias2<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%>% /* = ((self::ET_CovariantAlias2|constructor#_#new#tearOff::T%) → void) → void */
   return self::ET_CovariantAlias2|constructor#<self::ET_CovariantAlias2|constructor#_#new#tearOff::T%>(f);