[flip-modifiers]: flip the flags for sealed classes and class modifiers

Includes several updates to tests that needed to land with this flip, as well as some other tests that needed to be updated and could land separately, but are being included here to expedite things.

Removes some unnecessary experimental release versions, as well as bringing up to date the generated files, which were previously out of sync with the yaml file.

TEST=bots

Change-Id: I71a86d7a86190069b504bd27d687f62b97a7251e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/285080
Commit-Queue: Jake Macdonald <jakemac@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>

pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart

@@ -11,7 +11,7 @@
 enum ExperimentalFlag {
   classModifiers(
       name: 'class-modifiers',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
       experimentEnabledVersion: const Version(3, 0),
       experimentReleasedVersion: const Version(3, 0)),
@@ -133,11 +133,11 @@ enum ExperimentalFlag {
       isEnabledByDefault: false,
       isExpired: false,
       experimentEnabledVersion: const Version(3, 0),
-      experimentReleasedVersion: const Version(2, 19)),
+      experimentReleasedVersion: const Version(3, 0)),
 
   sealedClass(
       name: 'sealed-class',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
       experimentEnabledVersion: const Version(3, 0),
       experimentReleasedVersion: const Version(3, 0)),

pkg/_fe_analyzer_shared/test/inheritance/data/function.dart

@@ -5,21 +5,26 @@
 /*library: nnbd=true*/
 
 /*class: A:A,Object*/
-class A implements Function {}
+class /*cfe|cfe:builder.error: SubtypeOfBaseOrFinalIsNotBaseFinalOrSealed*/ A
+    implements /*analyzer.error: CompileTimeErrorCode.FINAL_CLASS_IMPLEMENTED_OUTSIDE_OF_LIBRARY*/
+        /*cfe|cfe:builder.error: FinalClassImplementedOutsideOfLibrary*/ Function {}
 
 /*class: B:B,Object*/
-class B extends Function {}
+class /*cfe|cfe:builder.error: SubtypeOfBaseOrFinalIsNotBaseFinalOrSealed*/ B
+    extends /*analyzer.error: CompileTimeErrorCode.FINAL_CLASS_EXTENDED_OUTSIDE_OF_LIBRARY*/ /*cfe|cfe:builder.error: FinalClassExtendedOutsideOfLibrary*/ Function {}
 
 /*cfe|cfe:builder.class: C:C,Object,_C&Object&Function*/
 /*analyzer.class: C:C,Object*/
-class C extends Object
+class /*cfe|cfe:builder.error: SubtypeOfBaseOrFinalIsNotBaseFinalOrSealed*/ C
+    extends Object
     with /*analyzer.error: CompileTimeErrorCode.CLASS_USED_AS_MIXIN*/
-        Function {}
+        /*cfe|cfe:builder.error: CantUseClassAsMixin*/ Function {}
 
 // CFE hides that this is a mixin declaration since its mixed in type has been
 // removed.
 /*cfe|cfe:builder.class: _C&Object&Function:Object,_C&Object&Function*/
 
 /*cfe|cfe:builder.class: D:D,Object*/
-class D = Object
-    with /*analyzer.error: CompileTimeErrorCode.CLASS_USED_AS_MIXIN*/ Function;
+class /*cfe|cfe:builder.error: SubtypeOfBaseOrFinalIsNotBaseFinalOrSealed*/ D = Object
+    with /*analyzer.error: CompileTimeErrorCode.CLASS_USED_AS_MIXIN*/ /*cfe|cfe:builder.error: CantUseClassAsMixin*/
+        Function;

pkg/analysis_server/test/src/services/correction/fix/remove_name_from_declaration_clause_test.dart

@@ -37,9 +37,11 @@ class DeprecatedImplementsFunctionTest extends FixProcessorTest {
 
   Future<void> test_oneName() async {
     await resolveTestCode('''
+// @dart = 2.19
 abstract class C implements Function {}
 ''');
     await assertHasFix('''
+// @dart = 2.19
 abstract class C {}
 ''');
   }

pkg/analyzer/lib/src/dart/analysis/experiments.g.dart

@@ -140,8 +140,8 @@ class ExperimentalFeatures {
     isEnabledByDefault: IsEnabledByDefault.class_modifiers,
     isExpired: IsExpired.class_modifiers,
     documentation: 'Class modifiers',
-    experimentalReleaseVersion: Version.parse('3.0.0'),
-    releaseVersion: null,
+    experimentalReleaseVersion: null,
+    releaseVersion: Version.parse('3.0.0'),
   );
 
   static final const_functions = ExperimentalFeature(
@@ -314,7 +314,7 @@ class ExperimentalFeatures {
     isEnabledByDefault: IsEnabledByDefault.records,
     isExpired: IsExpired.records,
     documentation: 'Records',
-    experimentalReleaseVersion: Version.parse('3.0.0'),
+    experimentalReleaseVersion: null,
     releaseVersion: null,
   );
 
@@ -324,8 +324,8 @@ class ExperimentalFeatures {
     isEnabledByDefault: IsEnabledByDefault.sealed_class,
     isExpired: IsExpired.sealed_class,
     documentation: 'Sealed class',
-    experimentalReleaseVersion: Version.parse('3.0.0'),
-    releaseVersion: null,
+    experimentalReleaseVersion: null,
+    releaseVersion: Version.parse('3.0.0'),
   );
 
   static final set_literals = ExperimentalFeature(
@@ -414,7 +414,7 @@ class ExperimentalFeatures {
 /// enabled by default.
 class IsEnabledByDefault {
   /// Default state of the experiment "class-modifiers"
-  static const bool class_modifiers = false;
+  static const bool class_modifiers = true;
 
   /// Default state of the experiment "const-functions"
   static const bool const_functions = false;
@@ -468,7 +468,7 @@ class IsEnabledByDefault {
   static const bool records = false;
 
   /// Default state of the experiment "sealed-class"
-  static const bool sealed_class = false;
+  static const bool sealed_class = true;
 
   /// Default state of the experiment "set-literals"
   static const bool set_literals = true;

pkg/dartdev/test/commands/run_test.dart

@@ -118,7 +118,7 @@ void run() {
     // VM service).
     //
     // See https://github.com/dart-lang/sdk/issues/50230
-    p = project(sdkConstraint: VersionConstraint.parse('>=2.19.0 <3.0.0'));
+    p = project(sdkConstraint: VersionConstraint.parse('>=3.0.0-0 <4.0.0'));
     p.file('main.dart', 'void main(args) { print("Record: \${(1, 2)}"); }');
     ProcessResult result = await p.run([
       'run',

pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart

@@ -61,7 +61,7 @@ class ExperimentalFlag {
 
   static const ExperimentalFlag classModifiers = const ExperimentalFlag(
       name: 'class-modifiers',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
       enabledVersion: const Version(3, 0),
       experimentEnabledVersion: const Version(3, 0),
@@ -201,11 +201,11 @@ class ExperimentalFlag {
       isExpired: false,
       enabledVersion: const Version(3, 0),
       experimentEnabledVersion: const Version(3, 0),
-      experimentReleasedVersion: const Version(2, 19));
+      experimentReleasedVersion: const Version(3, 0));
 
   static const ExperimentalFlag sealedClass = const ExperimentalFlag(
       name: 'sealed-class',
-      isEnabledByDefault: false,
+      isEnabledByDefault: true,
       isExpired: false,
       enabledVersion: const Version(3, 0),
       experimentEnabledVersion: const Version(3, 0),

pkg/front_end/messages.yaml

@@ -541,7 +541,7 @@ WithBeforeExtends:
   problemMessage: "The extends clause must be before the with clause."
   correctionMessage: "Try moving the extends clause before the with clause."
   analyzerCode: ParserErrorCode.WITH_BEFORE_EXTENDS
-  script: "class B {} class C {} class A with B extends C {}"
+  script: "mixin B {} class C {} class A with B extends C {}"
 
 ImplementsBeforeExtends:
   index: 44
@@ -596,8 +596,8 @@ MultipleClauses:
   analyzerCode: ParserErrorCode.MULTIPLE_CLAUSES
   index: 121
   script:
-    - "class B {} enum A implements B implements C, D { v; }"
-    - "class B {} enum A with B with C, D { v; }"
+    - "mixin B {} enum A implements B implements C, D { v; }"
+    - "mixin B {} enum A with B with C, D { v; }"
 
 OutOfOrderClauses:
   problemMessage: "The '#string' clause must come before the '#string2' clause."
@@ -5891,6 +5891,7 @@ MixinInheritsFromNotObject:
   problemMessage: "The class '#name' can't be used as a mixin because it extends a class other than 'Object'."
   analyzerCode: MIXIN_INHERITS_FROM_NOT_OBJECT
   script: |
+    // @dart=2.19
     class Base {}
     class Mixin extends Base {}
     class C extends Base with Mixin {}

pkg/front_end/test/macros/application/data/package_config.json

@@ -8,11 +8,13 @@
     {
       "name": "meta",
       "rootUri": "../../../../../meta/",
-      "packageUri": "lib/"
+      "packageUri": "lib/",
+      "languageVersion": "2.12"
     },
     {
       "name": "_fe_analyzer_shared",
-      "rootUri": "../../../../../_fe_analyzer_shared/lib/"
+      "rootUri": "../../../../../_fe_analyzer_shared/lib/",
+      "languageVersion": "2.17"
     }
   ]
-}
+}

pkg/front_end/test/macros/application/data/tests/sequence.dart

@@ -184,7 +184,7 @@ augment class Class7c {
   method() {}
 }
 */
-class Class7c {}
+mixin Class7c {}
 
 @SequenceMacro(0)
 /*class: Class7b:
@@ -204,4 +204,4 @@ augment class Class7a {
   method() {}
 }
 */
-class Class7a {}
+mixin Class7a {}

pkg/front_end/test/macros/application/data/tests/sequence.dart.expect

@@ -110,10 +110,7 @@ class Class7d extends self::_Class7d&Class7b&Class7c {
   method /* from org-dartlang-augmentation:/a/b/c/main.dart-17 */ method2() → dynamic {}
 }
 @#C2
-class Class7c extends core::Object {
-  synthetic constructor •() → self::Class7c
-    : super core::Object::•()
-    ;
+class Class7c extends core::Object /*isMixinDeclaration*/  {
   method /* from org-dartlang-augmentation:/a/b/c/main.dart-16 */ method() → dynamic {}
 }
 abstract class _Class7b&Object&Class7a = core::Object with self::Class7a /*isAnonymousMixin,hasConstConstructor*/  {
@@ -131,10 +128,7 @@ class Class7b extends self::_Class7b&Object&Class7a {
   method /* from org-dartlang-augmentation:/a/b/c/main.dart-15 */ method1() → dynamic {}
 }
 @#C2
-class Class7a extends core::Object {
-  synthetic constructor •() → self::Class7a
-    : super core::Object::•()
-    ;
+class Class7a extends core::Object /*isMixinDeclaration*/  {
   method /* from org-dartlang-augmentation:/a/b/c/main.dart-14 */ method() → dynamic {}
 }
 

pkg/front_end/test/macros/declaration/data/package_config.json

@@ -11,7 +11,8 @@
     },
     {
       "name": "_fe_analyzer_shared",
-      "rootUri": "../../../../../_fe_analyzer_shared/lib/"
+      "rootUri": "../../../../../_fe_analyzer_shared/lib/",
+      "languageVersion": "2.17"
     }
   ]
-}
+}

pkg/front_end/test/macros/incremental/data/package_config.json

@@ -8,11 +8,13 @@
     {
       "name": "meta",
       "rootUri": "../../../../../meta/",
-      "packageUri": "lib/"
+      "packageUri": "lib/",
+      "languageVersion": "2.12"
     },
     {
       "name": "_fe_analyzer_shared",
-      "rootUri": "../../../../../_fe_analyzer_shared/lib/"
+      "rootUri": "../../../../../_fe_analyzer_shared/lib/",
+      "languageVersion": "2.17"
     }
   ]
-}
+}

pkg/front_end/testcases/dartino/add_named_mixin_application.incremental.yaml

@@ -4,7 +4,7 @@
 
 main.dart.patch: |
   // Test that we can add a mixin application.
-  class A {}
+  mixin class A {}
   <<<< []
   ==== []
   class C = Object with A;

pkg/front_end/testcases/dartino/remove_named_mixin_application.incremental.yaml

@@ -4,7 +4,7 @@
 
 main.dart.patch: |
   // Test that we can remove a mixin application.
-  class A {}
+  mixin class A {}
   <<<< []
   class C = Object with A;
   ==== []

pkg/front_end/testcases/dartino/unchanged_named_mixin_application.incremental.yaml

@@ -4,7 +4,7 @@
 
 main.dart.patch: |
   // Test that we can handle a mixin application that doesn't change.
-  class A {}
+  mixin A {}
   class C = Object with A;
 
   main() {

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart

@@ -2,25 +2,29 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-abstract class A extends Enum { // Ok.
+abstract mixin class A extends Enum {
+  // Error.
   int get foo => index;
 }
 
 enum EA with A { element } // Error.
 
-abstract class B implements Enum { // Ok.
+abstract mixin class B implements Enum {
+  // Ok.
   int get foo => index;
 }
 
 enum EB with B { element }
 
-mixin M on Enum { // Ok.
+mixin M on Enum {
+  // Ok.
   int get foo => index;
 }
 
 enum EM with M { element }
 
-mixin N implements Enum { // Ok.
+mixin N implements Enum {
+  // Ok.
   int get foo => index;
 }
 
@@ -33,7 +37,6 @@ expectEquals(x, y) {
 }
 
 main() {
-  expectEquals(EA.element.foo, EA.element.index);
   expectEquals(EB.element.foo, EB.element.index);
   expectEquals(EM.element.foo, EM.element.index);
   expectEquals(EN.element.foo, EN.element.index);

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.strong.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     : super core::Enum::•()
     ;
@@ -32,7 +40,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     : super core::Object::•()
     ;
@@ -101,7 +109,6 @@ static method expectEquals(dynamic x, dynamic y) → dynamic {
   }
 }
 static method main() → dynamic {
-  self::expectEquals(#C3.{self::_EA&_Enum&A::foo}{core::int}, #C3.{core::_Enum::index}{core::int});
   self::expectEquals(#C5.{self::_EB&_Enum&B::foo}{core::int}, #C5.{core::_Enum::index}{core::int});
   self::expectEquals(#C7.{self::_EM&_Enum&M::foo}{core::int}, #C7.{core::_Enum::index}{core::int});
   self::expectEquals(#C9.{self::_EN&_Enum&N::foo}{core::int}, #C9.{core::_Enum::index}{core::int});
@@ -123,13 +130,13 @@ constants  {
 
 Constructor coverage from constants:
 org-dartlang-testcase:///enum_as_supertype.dart:
-- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
-- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
+- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
+- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
-- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
+- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)
+- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.strong.transformed.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     : super core::Enum::•()
     ;
@@ -32,7 +40,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     : super core::Object::•()
     ;
@@ -101,7 +109,6 @@ static method expectEquals(dynamic x, dynamic y) → dynamic {
   }
 }
 static method main() → dynamic {
-  self::expectEquals(#C3.{self::_EA&_Enum&A::foo}{core::int}, #C3.{core::_Enum::index}{core::int});
   self::expectEquals(#C5.{self::_EB&_Enum&B::foo}{core::int}, #C5.{core::_Enum::index}{core::int});
   self::expectEquals(#C7.{self::_EM&_Enum&M::foo}{core::int}, #C7.{core::_Enum::index}{core::int});
   self::expectEquals(#C9.{self::_EN&_Enum&N::foo}{core::int}, #C9.{core::_Enum::index}{core::int});
@@ -123,13 +130,13 @@ constants  {
 
 Constructor coverage from constants:
 org-dartlang-testcase:///enum_as_supertype.dart:
-- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
-- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
+- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
+- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
-- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
+- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)
+- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.textual_outline.expect

@@ -1,10 +1,10 @@
-abstract class A extends Enum {
+abstract mixin class A extends Enum {
   int get foo => index;
 }
 
 enum EA with A { element }
 
-abstract class B implements Enum {
+abstract mixin class B implements Enum {
   int get foo => index;
 }
 

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.textual_outline_modelled.expect

@@ -1,8 +1,8 @@
-abstract class A extends Enum {
+abstract mixin class A extends Enum {
   int get foo => index;
 }
 
-abstract class B implements Enum {
+abstract mixin class B implements Enum {
   int get foo => index;
 }
 

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.weak.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     : super core::Enum::•()
     ;
@@ -32,7 +40,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     : super core::Object::•()
     ;
@@ -101,7 +109,6 @@ static method expectEquals(dynamic x, dynamic y) → dynamic {
   }
 }
 static method main() → dynamic {
-  self::expectEquals(#C3.{self::_EA&_Enum&A::foo}{core::int}, #C3.{core::_Enum::index}{core::int});
   self::expectEquals(#C5.{self::_EB&_Enum&B::foo}{core::int}, #C5.{core::_Enum::index}{core::int});
   self::expectEquals(#C7.{self::_EM&_Enum&M::foo}{core::int}, #C7.{core::_Enum::index}{core::int});
   self::expectEquals(#C9.{self::_EN&_Enum&N::foo}{core::int}, #C9.{core::_Enum::index}{core::int});
@@ -123,13 +130,13 @@ constants  {
 
 Constructor coverage from constants:
 org-dartlang-testcase:///enum_as_supertype.dart:
-- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
-- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
+- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
+- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
-- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
+- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)
+- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.weak.modular.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     : super core::Enum::•()
     ;
@@ -32,7 +40,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     : super core::Object::•()
     ;
@@ -101,7 +109,6 @@ static method expectEquals(dynamic x, dynamic y) → dynamic {
   }
 }
 static method main() → dynamic {
-  self::expectEquals(#C3.{self::_EA&_Enum&A::foo}{core::int}, #C3.{core::_Enum::index}{core::int});
   self::expectEquals(#C5.{self::_EB&_Enum&B::foo}{core::int}, #C5.{core::_Enum::index}{core::int});
   self::expectEquals(#C7.{self::_EM&_Enum&M::foo}{core::int}, #C7.{core::_Enum::index}{core::int});
   self::expectEquals(#C9.{self::_EN&_Enum&N::foo}{core::int}, #C9.{core::_Enum::index}{core::int});
@@ -123,13 +130,13 @@ constants  {
 
 Constructor coverage from constants:
 org-dartlang-testcase:///enum_as_supertype.dart:
-- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
-- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
+- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
+- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
-- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
+- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)
+- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.weak.outline.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     ;
   get foo() → core::int
@@ -30,7 +38,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     ;
   get foo() → core::int
@@ -96,12 +104,12 @@ static method main() → dynamic
 
 
 Extra constant evaluation status:
-Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:9:6 -> ListConstant(const <EA*>[const EA{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:9:18 -> InstanceConstant(const EA{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:15:6 -> ListConstant(const <EB*>[const EB{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:15:18 -> InstanceConstant(const EB{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:21:6 -> ListConstant(const <EM*>[const EM{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:21:18 -> InstanceConstant(const EM{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:27:6 -> ListConstant(const <EN*>[const EN{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:27:18 -> InstanceConstant(const EN{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:10:6 -> ListConstant(const <EA*>[const EA{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:10:18 -> InstanceConstant(const EA{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:17:6 -> ListConstant(const <EB*>[const EB{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:17:18 -> InstanceConstant(const EB{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:24:6 -> ListConstant(const <EM*>[const EM{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:24:18 -> InstanceConstant(const EM{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///enum_as_supertype.dart:31:6 -> ListConstant(const <EN*>[const EN{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///enum_as_supertype.dart:31:18 -> InstanceConstant(const EN{})
 Extra constant evaluation: evaluated: 32, effectively constant: 8

pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart.weak.transformed.expect

@@ -2,14 +2,22 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:9:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:5:32: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
+// abstract mixin class A extends Enum {
+//                                ^
+//
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype.dart:10:14: Error: The class 'A' can't be used as a mixin because it extends a class other than 'Object'.
 // enum EA with A { element } // Error.
 //              ^
 //
 import self as self;
 import "dart:core" as core;
 
-abstract class A extends core::Enum {
+abstract mixin class A extends core::Enum {
   synthetic constructor •() → self::A
     : super core::Enum::•()
     ;
@@ -32,7 +40,7 @@ class EA extends self::_EA&_Enum&A /*isEnum*/  {
   method _enumToString() → core::String
     return "EA.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class B extends core::Object implements core::Enum {
+abstract mixin class B extends core::Object implements core::Enum {
   synthetic constructor •() → self::B
     : super core::Object::•()
     ;
@@ -101,7 +109,6 @@ static method expectEquals(dynamic x, dynamic y) → dynamic {
   }
 }
 static method main() → dynamic {
-  self::expectEquals(#C3.{self::_EA&_Enum&A::foo}{core::int}, #C3.{core::_Enum::index}{core::int});
   self::expectEquals(#C5.{self::_EB&_Enum&B::foo}{core::int}, #C5.{core::_Enum::index}{core::int});
   self::expectEquals(#C7.{self::_EM&_Enum&M::foo}{core::int}, #C7.{core::_Enum::index}{core::int});
   self::expectEquals(#C9.{self::_EN&_Enum&N::foo}{core::int}, #C9.{core::_Enum::index}{core::int});
@@ -123,13 +130,13 @@ constants  {
 
 Constructor coverage from constants:
 org-dartlang-testcase:///enum_as_supertype.dart:
-- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
-- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:9:6)
+- EA. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
+- _EA&_Enum&A. (from org-dartlang-testcase:///enum_as_supertype.dart:10:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:15:6)
-- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:21:6)
-- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
-- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:27:6)
+- EB. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- _EB&_Enum&B. (from org-dartlang-testcase:///enum_as_supertype.dart:17:6)
+- EM. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- _EM&_Enum&M. (from org-dartlang-testcase:///enum_as_supertype.dart:24:6)
+- EN. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)
+- _EN&_Enum&N. (from org-dartlang-testcase:///enum_as_supertype.dart:31:6)

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.strong.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.strong.transformed.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.weak.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.weak.modular.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.weak.outline.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart.weak.transformed.expect

@@ -2,6 +2,10 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:17: Error: The class 'Enum' can't be extended outside of its library because it's an interface class.
+// class A extends Enum { // Error.
+//                 ^
+//
 // pkg/front_end/testcases/enhanced_enums/enum_as_supertype_error.dart:5:7: Error: Non-abstract class 'A' has 'Enum' as a superinterface.
 // class A extends Enum { // Error.
 //       ^

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart

@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-class A1 {
+mixin class A1 {
   int get hashCode => 42;
 }
 
@@ -10,7 +10,7 @@ enum E1 with A1 { // Error.
   element
 }
 
-class A2 {
+mixin class A2 {
   int get values => 42;
 }
 
@@ -18,7 +18,7 @@ enum E2 with A2 { // Error.
   element
 }
 
-class A3 {
+mixin class A3 {
   int get index => 42;
 }
 
@@ -26,7 +26,7 @@ enum E3 with A3 { // Error.
   element
 }
 
-class A4 {
+mixin class A4 {
   bool operator==(Object other) => true;
 }
 
@@ -66,7 +66,7 @@ enum E8 with M8 { // Error.
   element
 }
 
-abstract class A9 {
+abstract mixin class A9 {
   int get index;
   int get hashCode;
   bool operator==(Object other);

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.strong.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     : super core::Object::•()
     ;
@@ -98,7 +98,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     : super core::Object::•()
     ;
@@ -121,7 +121,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     : super core::Object::•()
     ;
@@ -144,7 +144,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     : super core::Object::•()
     ;
@@ -247,7 +247,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     : super core::Object::•()
     ;

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.strong.transformed.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     : super core::Object::•()
     ;
@@ -98,7 +98,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     : super core::Object::•()
     ;
@@ -121,7 +121,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     : super core::Object::•()
     ;
@@ -144,7 +144,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     : super core::Object::•()
     ;
@@ -247,7 +247,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     : super core::Object::•()
     ;

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.textual_outline.expect

@@ -1,22 +1,22 @@
-class A1 {
+mixin class A1 {
   int get hashCode => 42;
 }
 
 enum E1 with A1 { element }
 
-class A2 {
+mixin class A2 {
   int get values => 42;
 }
 
 enum E2 with A2 { element }
 
-class A3 {
+mixin class A3 {
   int get index => 42;
 }
 
 enum E3 with A3 { element }
 
-class A4 {
+mixin class A4 {
   bool operator ==(Object other) => true;
 }
 
@@ -46,7 +46,7 @@ mixin M8 {
 
 enum E8 with M8 { element }
 
-abstract class A9 {
+abstract mixin class A9 {
   int get index;
   int get hashCode;
   bool operator ==(Object other);

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.textual_outline_modelled.expect

@@ -1,25 +1,9 @@
-abstract class A9 {
+abstract mixin class A9 {
   bool operator ==(Object other);
   int get hashCode;
   int get index;
 }
 
-class A1 {
-  int get hashCode => 42;
-}
-
-class A2 {
-  int get values => 42;
-}
-
-class A3 {
-  int get index => 42;
-}
-
-class A4 {
-  bool operator ==(Object other) => true;
-}
-
 enum E1 with A1 { element }
 
 enum E10 with M10 { element }
@@ -58,3 +42,19 @@ mixin M7 {
 mixin M8 {
   bool operator ==(Object other) => true;
 }
+
+mixin class A1 {
+  int get hashCode => 42;
+}
+
+mixin class A2 {
+  int get values => 42;
+}
+
+mixin class A3 {
+  int get index => 42;
+}
+
+mixin class A4 {
+  bool operator ==(Object other) => true;
+}

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.weak.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     : super core::Object::•()
     ;
@@ -98,7 +98,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     : super core::Object::•()
     ;
@@ -121,7 +121,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     : super core::Object::•()
     ;
@@ -144,7 +144,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     : super core::Object::•()
     ;
@@ -247,7 +247,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     : super core::Object::•()
     ;

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.weak.modular.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     : super core::Object::•()
     ;
@@ -98,7 +98,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     : super core::Object::•()
     ;
@@ -121,7 +121,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     : super core::Object::•()
     ;
@@ -144,7 +144,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     : super core::Object::•()
     ;
@@ -247,7 +247,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     : super core::Object::•()
     ;

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.weak.outline.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     ;
   get hashCode() → core::int
@@ -96,7 +96,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     ;
   get values() → core::int
@@ -117,7 +117,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     ;
   get index() → core::int
@@ -138,7 +138,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     ;
   operator ==(core::Object other) → core::bool
@@ -235,7 +235,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     ;
   abstract get index() → core::int;

pkg/front_end/testcases/enhanced_enums/inherited_restricted_members.dart.weak.transformed.expect

@@ -75,7 +75,7 @@ library /*isNonNullableByDefault*/;
 import self as self;
 import "dart:core" as core;
 
-class A1 extends core::Object {
+mixin class A1 extends core::Object {
   synthetic constructor •() → self::A1
     : super core::Object::•()
     ;
@@ -98,7 +98,7 @@ class E1 extends self::_E1&_Enum&A1 /*isEnum*/  {
   method _enumToString() → core::String
     return "E1.${this.{core::_Enum::_name}{core::String}}";
 }
-class A2 extends core::Object {
+mixin class A2 extends core::Object {
   synthetic constructor •() → self::A2
     : super core::Object::•()
     ;
@@ -121,7 +121,7 @@ class E2 extends self::_E2&_Enum&A2 /*isEnum*/  {
   method _enumToString() → core::String
     return "E2.${this.{core::_Enum::_name}{core::String}}";
 }
-class A3 extends core::Object {
+mixin class A3 extends core::Object {
   synthetic constructor •() → self::A3
     : super core::Object::•()
     ;
@@ -144,7 +144,7 @@ class E3 extends self::_E3&_Enum&A3 /*isEnum*/  {
   method _enumToString() → core::String
     return "E3.${this.{core::_Enum::_name}{core::String}}";
 }
-class A4 extends core::Object {
+mixin class A4 extends core::Object {
   synthetic constructor •() → self::A4
     : super core::Object::•()
     ;
@@ -247,7 +247,7 @@ class E8 extends self::_E8&_Enum&M8 /*isEnum*/  {
   method _enumToString() → core::String
     return "E8.${this.{core::_Enum::_name}{core::String}}";
 }
-abstract class A9 extends core::Object {
+abstract mixin class A9 extends core::Object {
   synthetic constructor •() → self::A9
     : super core::Object::•()
     ;

pkg/front_end/testcases/enhanced_enums/issue49236.dart

@@ -6,7 +6,7 @@ mixin M {
   String toString() => "M";
 }
 
-abstract class A {
+abstract mixin class A {
   String toString() => "A";
 }
 
@@ -14,9 +14,7 @@ abstract class B implements Enum {
   String toString() => "B";
 }
 
-enum E1 with M {
-  element
-}
+enum E1 with M { element }
 
 enum E2 with M {
   element;
@@ -30,9 +28,7 @@ enum E3 {
   String toString() => "E3";
 }
 
-enum E4 implements B {
-  element
-}
+enum E4 implements B { element }
 
 enum E5 implements B {
   element;
@@ -40,9 +36,7 @@ enum E5 implements B {
   String toString() => "E5";
 }
 
-enum E6 with A {
-  element
-}
+enum E6 with A { element }
 
 enum E7 with A {
   element;

pkg/front_end/testcases/enhanced_enums/issue49236.dart.strong.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     return "M";
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     : super core::Object::•()
     ;
@@ -160,12 +160,12 @@ org-dartlang-testcase:///issue49236.dart:
 - _E1&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:17:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- E2. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- E3. (from org-dartlang-testcase:///issue49236.dart:27:6)
-- E4. (from org-dartlang-testcase:///issue49236.dart:33:6)
-- E5. (from org-dartlang-testcase:///issue49236.dart:37:6)
-- E6. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- E7. (from org-dartlang-testcase:///issue49236.dart:47:6)
-- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:47:6)
+- E2. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- E3. (from org-dartlang-testcase:///issue49236.dart:25:6)
+- E4. (from org-dartlang-testcase:///issue49236.dart:31:6)
+- E5. (from org-dartlang-testcase:///issue49236.dart:33:6)
+- E6. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- E7. (from org-dartlang-testcase:///issue49236.dart:41:6)
+- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:41:6)

pkg/front_end/testcases/enhanced_enums/issue49236.dart.strong.transformed.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     return "M";
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     : super core::Object::•()
     ;
@@ -160,12 +160,12 @@ org-dartlang-testcase:///issue49236.dart:
 - _E1&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:17:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- E2. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- E3. (from org-dartlang-testcase:///issue49236.dart:27:6)
-- E4. (from org-dartlang-testcase:///issue49236.dart:33:6)
-- E5. (from org-dartlang-testcase:///issue49236.dart:37:6)
-- E6. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- E7. (from org-dartlang-testcase:///issue49236.dart:47:6)
-- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:47:6)
+- E2. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- E3. (from org-dartlang-testcase:///issue49236.dart:25:6)
+- E4. (from org-dartlang-testcase:///issue49236.dart:31:6)
+- E5. (from org-dartlang-testcase:///issue49236.dart:33:6)
+- E6. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- E7. (from org-dartlang-testcase:///issue49236.dart:41:6)
+- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:41:6)

pkg/front_end/testcases/enhanced_enums/issue49236.dart.textual_outline.expect

@@ -2,7 +2,7 @@ mixin M {
   String toString() => "M";
 }
 
-abstract class A {
+abstract mixin class A {
   String toString() => "A";
 }
 

pkg/front_end/testcases/enhanced_enums/issue49236.dart.textual_outline_modelled.expect

@@ -1,11 +1,11 @@
-abstract class A {
-  String toString() => "A";
-}
-
 abstract class B implements Enum {
   String toString() => "B";
 }
 
+abstract mixin class A {
+  String toString() => "A";
+}
+
 checkEqual(x, y) {}
 
 enum E1 with M { element }

pkg/front_end/testcases/enhanced_enums/issue49236.dart.weak.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     return "M";
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     : super core::Object::•()
     ;
@@ -160,12 +160,12 @@ org-dartlang-testcase:///issue49236.dart:
 - _E1&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:17:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- E2. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- E3. (from org-dartlang-testcase:///issue49236.dart:27:6)
-- E4. (from org-dartlang-testcase:///issue49236.dart:33:6)
-- E5. (from org-dartlang-testcase:///issue49236.dart:37:6)
-- E6. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- E7. (from org-dartlang-testcase:///issue49236.dart:47:6)
-- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:47:6)
+- E2. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- E3. (from org-dartlang-testcase:///issue49236.dart:25:6)
+- E4. (from org-dartlang-testcase:///issue49236.dart:31:6)
+- E5. (from org-dartlang-testcase:///issue49236.dart:33:6)
+- E6. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- E7. (from org-dartlang-testcase:///issue49236.dart:41:6)
+- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:41:6)

pkg/front_end/testcases/enhanced_enums/issue49236.dart.weak.modular.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     return "M";
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     : super core::Object::•()
     ;
@@ -160,12 +160,12 @@ org-dartlang-testcase:///issue49236.dart:
 - _E1&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:17:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- E2. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- E3. (from org-dartlang-testcase:///issue49236.dart:27:6)
-- E4. (from org-dartlang-testcase:///issue49236.dart:33:6)
-- E5. (from org-dartlang-testcase:///issue49236.dart:37:6)
-- E6. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- E7. (from org-dartlang-testcase:///issue49236.dart:47:6)
-- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:47:6)
+- E2. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- E3. (from org-dartlang-testcase:///issue49236.dart:25:6)
+- E4. (from org-dartlang-testcase:///issue49236.dart:31:6)
+- E5. (from org-dartlang-testcase:///issue49236.dart:33:6)
+- E6. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- E7. (from org-dartlang-testcase:///issue49236.dart:41:6)
+- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:41:6)

pkg/front_end/testcases/enhanced_enums/issue49236.dart.weak.outline.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     ;
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     ;
   method toString() → core::String
@@ -121,17 +121,17 @@ static method main() → dynamic
 
 Extra constant evaluation status:
 Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:17:6 -> ListConstant(const <E1*>[const E1{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:18:3 -> InstanceConstant(const E1{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:21:6 -> ListConstant(const <E2*>[const E2{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:22:3 -> InstanceConstant(const E2{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:27:6 -> ListConstant(const <E3*>[const E3{_Enum.index: 0, _Enum._name: "element"}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:28:3 -> InstanceConstant(const E3{_Enum.index: 0, _Enum._name: "element"})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:33:6 -> ListConstant(const <E4*>[const E4{_Enum.index: 0, _Enum._name: "element"}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:34:3 -> InstanceConstant(const E4{_Enum.index: 0, _Enum._name: "element"})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:37:6 -> ListConstant(const <E5*>[const E5{_Enum.index: 0, _Enum._name: "element"}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:38:3 -> InstanceConstant(const E5{_Enum.index: 0, _Enum._name: "element"})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:43:6 -> ListConstant(const <E6*>[const E6{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:44:3 -> InstanceConstant(const E6{})
-Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:47:6 -> ListConstant(const <E7*>[const E7{}])
-Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:48:3 -> InstanceConstant(const E7{})
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:17:18 -> InstanceConstant(const E1{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:19:6 -> ListConstant(const <E2*>[const E2{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:20:3 -> InstanceConstant(const E2{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:25:6 -> ListConstant(const <E3*>[const E3{_Enum.index: 0, _Enum._name: "element"}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:26:3 -> InstanceConstant(const E3{_Enum.index: 0, _Enum._name: "element"})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:31:6 -> ListConstant(const <E4*>[const E4{_Enum.index: 0, _Enum._name: "element"}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:31:24 -> InstanceConstant(const E4{_Enum.index: 0, _Enum._name: "element"})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:33:6 -> ListConstant(const <E5*>[const E5{_Enum.index: 0, _Enum._name: "element"}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:34:3 -> InstanceConstant(const E5{_Enum.index: 0, _Enum._name: "element"})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:39:6 -> ListConstant(const <E6*>[const E6{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:39:18 -> InstanceConstant(const E6{})
+Evaluated: ListLiteral @ org-dartlang-testcase:///issue49236.dart:41:6 -> ListConstant(const <E7*>[const E7{}])
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///issue49236.dart:42:3 -> InstanceConstant(const E7{})
 Extra constant evaluation: evaluated: 53, effectively constant: 14

pkg/front_end/testcases/enhanced_enums/issue49236.dart.weak.transformed.expect

@@ -6,7 +6,7 @@ abstract class M extends core::Object /*isMixinDeclaration*/  {
   method toString() → core::String
     return "M";
 }
-abstract class A extends core::Object {
+abstract mixin class A extends core::Object {
   synthetic constructor •() → self::A
     : super core::Object::•()
     ;
@@ -160,12 +160,12 @@ org-dartlang-testcase:///issue49236.dart:
 - _E1&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:17:6)
 - _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart)
 - Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)
-- E2. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:21:6)
-- E3. (from org-dartlang-testcase:///issue49236.dart:27:6)
-- E4. (from org-dartlang-testcase:///issue49236.dart:33:6)
-- E5. (from org-dartlang-testcase:///issue49236.dart:37:6)
-- E6. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:43:6)
-- E7. (from org-dartlang-testcase:///issue49236.dart:47:6)
-- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:47:6)
+- E2. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- _E2&_Enum&M. (from org-dartlang-testcase:///issue49236.dart:19:6)
+- E3. (from org-dartlang-testcase:///issue49236.dart:25:6)
+- E4. (from org-dartlang-testcase:///issue49236.dart:31:6)
+- E5. (from org-dartlang-testcase:///issue49236.dart:33:6)
+- E6. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- _E6&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:39:6)
+- E7. (from org-dartlang-testcase:///issue49236.dart:41:6)
+- _E7&_Enum&A. (from org-dartlang-testcase:///issue49236.dart:41:6)

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart

@@ -6,9 +6,9 @@ typedef ContravariantUse<T> = Function(T);
 
 typedef InvariantUse<T> = T Function(T);
 
-class Empty {}
+mixin Empty {}
 
-class A<T> {}
+mixin class A<T> {}
 
 class B<T> extends A<Function(T)> {}
 

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.strong.expect

@@ -115,12 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    : super core::Object::•()
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.strong.transformed.expect

@@ -115,12 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    : super core::Object::•()
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.textual_outline.expect

@@ -1,9 +1,8 @@
 typedef ContravariantUse<T> = Function(T);
 typedef InvariantUse<T> = T Function(T);
+mixin Empty {}
 
-class Empty {}
-
-class A<T> {}
+mixin class A<T> {}
 
 class B<T> extends A<Function(T)> {}
 

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.textual_outline_modelled.expect

@@ -1,5 +1,3 @@
-class A<T> {}
-
 class B<T> extends A<Function(T)> {}
 
 class Bc<T> extends A<ContravariantUse<T>> {}
@@ -19,8 +17,6 @@ class E<T> = A<Function(T)> with Empty;
 class Ec<T> = A<ContravariantUse<T>> with Empty;
 class Ei<T> = A<InvariantUse<T>> with Empty;
 
-class Empty {}
-
 class F<T> extends Object with A<Function(T)> {}
 
 class Fc<T> extends Object with A<ContravariantUse<T>> {}
@@ -73,5 +69,9 @@ class Jffc<T> extends A<Function(Function(ContravariantUse<T>))> {}
 class Jfff<T> extends A<Function(Function(Function(T)))> {}
 
 main() {}
+mixin Empty {}
+
+mixin class A<T> {}
+
 typedef ContravariantUse<T> = Function(T);
 typedef InvariantUse<T> = T Function(T);

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.weak.expect

@@ -115,12 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    : super core::Object::•()
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.weak.modular.expect

@@ -115,12 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    : super core::Object::•()
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.weak.outline.expect

@@ -115,11 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     ;
 }

pkg/front_end/testcases/general/bad_type_variable_uses_in_supertypes.dart.weak.transformed.expect

@@ -115,12 +115,9 @@ import "dart:core" as core;
 
 typedef ContravariantUse<contravariant T extends core::Object? = dynamic> = (T%) → dynamic;
 typedef InvariantUse<invariant T extends core::Object? = dynamic> = (T%) → T%;
-class Empty extends core::Object {
-  synthetic constructor •() → self::Empty
-    : super core::Object::•()
-    ;
+abstract class Empty extends core::Object /*isMixinDeclaration*/  {
 }
-class A<T extends core::Object? = dynamic> extends core::Object {
+mixin class A<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::A<self::A::T%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/base_class_declaration.dart

@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.18
+// @dart=2.19
 
 base class A {}
 

pkg/front_end/testcases/general/base_class_declaration.dart.strong.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/base_class_declaration.dart.strong.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/base_class_declaration.dart.textual_outline.expect

@@ -1,6 +1,7 @@
-// @dart = 2.18
+// @dart = 2.19
 base class A {}
+
 abstract base class B {}
-base
-mixin M {}
+
+base mixin M {}
 base class C = Object with M;

pkg/front_end/testcases/general/base_class_declaration.dart.textual_outline_modelled.expect

@@ -0,0 +1,8 @@
+// @dart = 2.19
+abstract base class B {}
+base class A {}
+---- unknown chunk starts ----
+base
+---- unknown chunk ends ----
+base class C = Object with M;
+mixin M {}

pkg/front_end/testcases/general/base_class_declaration.dart.weak.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/base_class_declaration.dart.weak.modular.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/base_class_declaration.dart.weak.outline.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/base_class_declaration.dart.weak.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class A {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract base class B {}
 //          ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base mixin M {}
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/base_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // base class C = Object with M;
 // ^^^^
+// pkg/front_end/testcases/general/base_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/bounds_supertypes.dart

@@ -2,13 +2,13 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-class Class<T> {}
+mixin class Class<T> {}
 
 class ConcreteClass implements Class<ConcreteClass> {}
 
 typedef F<X extends Class<X>> = Class<X>;
 
-class G<X extends Class<X>> {}
+mixin class G<X extends Class<X>> {}
 
 class ExtendsT1 extends F {} // Error
 

pkg/front_end/testcases/general/bounds_supertypes.dart.strong.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     : super core::Object::•()
     ;
@@ -714,7 +714,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
     : super core::Object::•()
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bounds_supertypes.dart.strong.transformed.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     : super core::Object::•()
     ;
@@ -714,7 +714,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
     : super core::Object::•()
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bounds_supertypes.dart.textual_outline.expect

@@ -1,10 +1,10 @@
-class Class<T> {}
+mixin class Class<T> {}
 
 class ConcreteClass implements Class<ConcreteClass> {}
 
 typedef F<X extends Class<X>> = Class<X>;
 
-class G<X extends Class<X>> {}
+mixin class G<X extends Class<X>> {}
 
 class ExtendsT1 extends F {}
 

pkg/front_end/testcases/general/bounds_supertypes.dart.textual_outline_modelled.expect

@@ -1,5 +1,3 @@
-class Class<T> {}
-
 class ConcreteClass implements Class<ConcreteClass> {}
 
 class ExtendsS1 extends G {}
@@ -34,8 +32,6 @@ class ExtendsT7 extends F<Object> {}
 
 class ExtendsT8 extends F<int> {}
 
-class G<X extends Class<X>> {}
-
 class ImplementsS1 implements G {}
 
 class ImplementsS2 implements G<dynamic> {}
@@ -213,4 +209,9 @@ mixin MixinOnT5 on F<ConcreteClass> {}
 mixin MixinOnT6 on F<Class<ConcreteClass>> {}
 mixin MixinOnT7 on F<Object> {}
 mixin MixinOnT8 on F<int> {}
+
+mixin class Class<T> {}
+
+mixin class G<X extends Class<X>> {}
+
 typedef F<X extends Class<X>> = Class<X>;

pkg/front_end/testcases/general/bounds_supertypes.dart.weak.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     : super core::Object::•()
     ;
@@ -714,7 +714,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
     : super core::Object::•()
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bounds_supertypes.dart.weak.modular.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     : super core::Object::•()
     ;
@@ -714,7 +714,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
     : super core::Object::•()
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/bounds_supertypes.dart.weak.outline.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     ;
 }
@@ -712,7 +712,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
   synthetic constructor •() → self::ConcreteClass
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     ;
 }

pkg/front_end/testcases/general/bounds_supertypes.dart.weak.transformed.expect

@@ -62,36 +62,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ExtendsS1 extends G {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:31:25: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS2 extends G<dynamic> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:33:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS3 extends G<Class> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:35:25: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS4 extends G<Class<dynamic>> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:41:25: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -99,18 +99,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS7 extends G<Object> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:43:25: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ExtendsS8 extends G<int> {} // Error
 //                         ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:45:31: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -172,36 +172,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class ImplementsS1 implements G {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:63:31: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS2 implements G<dynamic> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:65:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS3 implements G<Class> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:67:31: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS4 implements G<Class<dynamic>> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:73:31: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -209,18 +209,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS7 implements G<Object> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:75:31: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class ImplementsS8 implements G<int> {} // Error
 //                               ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:77:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -337,36 +337,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumImplementsS1 implements G /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:127:34: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS2 implements G<dynamic> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:129:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS3 implements G<Class> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:131:34: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS4 implements G<Class<dynamic>> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:137:34: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -374,18 +374,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS7 implements G<Object> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:139:34: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumImplementsS8 implements G<int> /* Error */ { a }
 //                                  ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:141:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
@@ -502,36 +502,36 @@ library /*isNonNullableByDefault*/;
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // mixin MixinOnS1 on G {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:191:20: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS2 on G<dynamic> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:193:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS3 on G<Class> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:195:20: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS4 on G<Class<dynamic>> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:201:20: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -539,18 +539,18 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS7 on G<Object> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:203:20: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // mixin MixinOnS8 on G<int> {} // Error
 //                    ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:217:28: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'F'.
 //  - 'Object' is from 'dart:core'.
@@ -577,54 +577,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS7 on G<Object> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:235:28: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // extension ExtensionOnS8 on G<int> {} // Error
 //                            ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:93:19: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // class WithS1 with G {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:95:19: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS2 with G<dynamic> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:97:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS3 with G<Class> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:99:19: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS4 with G<Class<dynamic>> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:105:19: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -632,54 +632,54 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // class WithS7 with G<Object> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:107:19: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // class WithS8 with G<int> {} // Error
 //                   ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:157:22: Error: Inferred type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try specifying type arguments explicitly so that they conform to the bounds.
 // enum EnumWithS1 with G /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:159:22: Error: Type argument 'dynamic' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS2 with G<dynamic> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:161:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS3 with G<Class> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:163:22: Error: Type argument 'Class<dynamic>' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS4 with G<Class<dynamic>> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:169:22: Error: Type argument 'Object' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Object' is from 'dart:core'.
@@ -687,24 +687,24 @@ library /*isNonNullableByDefault*/;
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS7 with G<Object> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 // pkg/front_end/testcases/general/bounds_supertypes.dart:171:22: Error: Type argument 'int' doesn't conform to the bound 'Class<X>' of the type variable 'X' on 'G'.
 //  - 'Class' is from 'pkg/front_end/testcases/general/bounds_supertypes.dart'.
 // Try changing type arguments so that they conform to the bounds.
 // enum EnumWithS8 with G<int> /* Error */ { a }
 //                      ^
-// pkg/front_end/testcases/general/bounds_supertypes.dart:11:9: Context: This is the type variable whose bound isn't conformed to.
-// class G<X extends Class<X>> {}
-//         ^
+// pkg/front_end/testcases/general/bounds_supertypes.dart:11:15: Context: This is the type variable whose bound isn't conformed to.
+// mixin class G<X extends Class<X>> {}
+//               ^
 //
 import self as self;
 import "dart:core" as core;
 
 typedef F<X extends self::Class<X> = self::Class<dynamic>> = self::Class<X>;
-class Class<T extends core::Object? = dynamic> extends core::Object {
+mixin class Class<T extends core::Object? = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T%>
     : super core::Object::•()
     ;
@@ -714,7 +714,7 @@ class ConcreteClass extends core::Object implements self::Class<self::ConcreteCl
     : super core::Object::•()
     ;
 }
-class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
+mixin class G<X extends self::Class<self::G::X> = self::Class<dynamic>> extends core::Object {
   synthetic constructor •() → self::G<self::G::X>
     : super core::Object::•()
     ;

pkg/front_end/testcases/general/duplicated_declarations.dart.strong.expect

@@ -316,7 +316,7 @@ library /*isNonNullableByDefault*/;
 //     ^^^^
 //
 // pkg/front_end/testcases/general/duplicated_declarations.dart:40:5: Error: The 'records' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to 2.19 or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 //   C.();
 //     ^
 // pkg/front_end/testcases/general/duplicated_declarations.dart:5:1: Context: This is the annotation that opts out this library from the 'records' language feature.

pkg/front_end/testcases/general/duplicated_declarations.dart.strong.transformed.expect

@@ -316,7 +316,7 @@ library /*isNonNullableByDefault*/;
 //     ^^^^
 //
 // pkg/front_end/testcases/general/duplicated_declarations.dart:40:5: Error: The 'records' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to 2.19 or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 //   C.();
 //     ^
 // pkg/front_end/testcases/general/duplicated_declarations.dart:5:1: Context: This is the annotation that opts out this library from the 'records' language feature.

pkg/front_end/testcases/general/duplicated_declarations.dart.weak.expect

@@ -316,7 +316,7 @@ library /*isNonNullableByDefault*/;
 //     ^^^^
 //
 // pkg/front_end/testcases/general/duplicated_declarations.dart:40:5: Error: The 'records' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to 2.19 or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 //   C.();
 //     ^
 // pkg/front_end/testcases/general/duplicated_declarations.dart:5:1: Context: This is the annotation that opts out this library from the 'records' language feature.

pkg/front_end/testcases/general/duplicated_declarations.dart.weak.modular.expect

@@ -316,7 +316,7 @@ library /*isNonNullableByDefault*/;
 //     ^^^^
 //
 // pkg/front_end/testcases/general/duplicated_declarations.dart:40:5: Error: The 'records' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to 2.19 or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 //   C.();
 //     ^
 // pkg/front_end/testcases/general/duplicated_declarations.dart:5:1: Context: This is the annotation that opts out this library from the 'records' language feature.

pkg/front_end/testcases/general/duplicated_declarations.dart.weak.transformed.expect

@@ -316,7 +316,7 @@ library /*isNonNullableByDefault*/;
 //     ^^^^
 //
 // pkg/front_end/testcases/general/duplicated_declarations.dart:40:5: Error: The 'records' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to 2.19 or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 //   C.();
 //     ^
 // pkg/front_end/testcases/general/duplicated_declarations.dart:5:1: Context: This is the annotation that opts out this library from the 'records' language feature.

pkg/front_end/testcases/general/final_class_declaration.dart.strong.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/final_class_declaration.dart.strong.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/final_class_declaration.dart.weak.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/final_class_declaration.dart.weak.modular.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/final_class_declaration.dart.weak.outline.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/final_class_declaration.dart.weak.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract final class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final mixin M {}
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/final_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // final class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/final_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart

@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.18
+// @dart=2.19
 
 interface class A {}
 

pkg/front_end/testcases/general/interface_class_declaration.dart.strong.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart.strong.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart.textual_outline.expect

@@ -1,6 +1,7 @@
-// @dart = 2.18
+// @dart = 2.19
 interface class A {}
+
 abstract interface class B {}
-interface
-mixin M {}
+
+interface mixin M {}
 interface class C = Object with M;

pkg/front_end/testcases/general/interface_class_declaration.dart.textual_outline_modelled.expect

@@ -0,0 +1,8 @@
+// @dart = 2.19
+abstract interface class B {}
+interface class A {}
+---- unknown chunk starts ----
+interface
+---- unknown chunk ends ----
+interface class C = Object with M;
+mixin M {}

pkg/front_end/testcases/general/interface_class_declaration.dart.weak.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart.weak.modular.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart.weak.outline.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/interface_class_declaration.dart.weak.transformed.expect

@@ -2,25 +2,37 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class A {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract interface class B {}
 //          ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:11:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface mixin M {}
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/interface_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // interface class C = Object with M;
 // ^^^^^^^^^
+// pkg/front_end/testcases/general/interface_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/mixin_class_declaration.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.19
+
 mixin class A {}
 
 abstract mixin class B {}

pkg/front_end/testcases/general/mixin_class_declaration.dart.strong.expect

@@ -2,20 +2,29 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // mixin class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:7:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract mixin class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:10:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // mixin class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/mixin_class_declaration.dart.strong.transformed.expect

@@ -2,20 +2,29 @@ library /*isNonNullableByDefault*/;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:7:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // mixin class A {}
 // ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:7:10: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:9:10: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // abstract mixin class B {}
 //          ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/mixin_class_declaration.dart:10:1: Error: This requires the experimental 'class-modifiers' language feature to be enabled.
-// Try passing the '--enable-experiment=class-modifiers' command line option.
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:12:1: Error: The 'class-modifiers' language feature is disabled for this library.
+// Try removing the `@dart=` annotation or setting the language version to 3.0 or higher.
 // mixin class C = Object with M;
 // ^^^^^
+// pkg/front_end/testcases/general/mixin_class_declaration.dart:5:1: Context: This is the annotation that opts out this library from the 'class-modifiers' language feature.
+// // @dart=2.19
+// ^^^^^^^^^^^^^
 //
 import self as self;
 import "dart:core" as core;

pkg/front_end/testcases/general/mixin_class_declaration.dart.textual_outline.expect

@@ -1,3 +1,4 @@
+// @dart = 2.19
 mixin class A {}
 
 abstract mixin class B {}

pkg/front_end/testcases/general/mixin_class_declaration.dart.textual_outline_modelled.expect

@@ -1,3 +1,4 @@
+// @dart = 2.19
 abstract mixin class B {}
 
 mixin M {}