Extension types. Apply substitution when copy superinterface members into extension types.

Change-Id: I93d8ab4582491bad262253eedc94dc63d33c5457
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/319900
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Phil Quitslund <pquitslund@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart

@@ -692,9 +692,10 @@ class InheritanceManager3 {
     final extensionCandidates = <Name, List<ExecutableElement>>{};
     final notExtensionCandidates = <Name, List<ExecutableElement>>{};
     for (final interface in augmented.interfaces) {
+      final substitution = Substitution.fromInterfaceType(interface);
       for (final entry in getInterface(interface.element).map.entries) {
         final name = entry.key;
-        final executable = entry.value;
+        final executable = ExecutableMember.from2(entry.value, substitution);
         if (executable.enclosingElement is ExtensionTypeElement) {
           (extensionCandidates[name] ??= []).add(executable);
         } else {

pkg/analyzer/test/src/dart/element/inheritance_manager3_test.dart

@@ -765,6 +765,34 @@ declared
 ''');
   }
 
+  test_noDeclaration_implementClass_generic_method() async {
+    final library = await buildLibrary(r'''
+class A<T> {
+  void foo(T a) {}
+}
+
+class B extends A<int> {}
+
+extension type C(B it) implements A<int> {}
+''');
+
+    final element = library.extensionType('C');
+    assertInterfaceText(element, r'''
+map
+  foo: MethodMember
+    base: self::@class::A::@method::foo
+    substitution: {T: int}
+  it: self::@extensionType::C::@getter::it
+declared
+  it: self::@extensionType::C::@getter::it
+redeclared
+  foo
+    MethodMember
+      base: self::@class::A::@method::foo
+      substitution: {T: int}
+''');
+  }
+
   test_noDeclaration_implementClass_implementExtensionType_hasConflict() async {
     final library = await buildLibrary(r'''
 class A {
@@ -932,6 +960,36 @@ redeclared
 ''');
   }
 
+  test_noDeclaration_implementExtensionType_generic_method() async {
+    final library = await buildLibrary(r'''
+extension type A<T>(T it) {
+  void foo(T a) {}
+}
+
+extension type B(int it) implements A<int> {}
+''');
+
+    final element = library.extensionType('B');
+    assertInterfaceText(element, r'''
+map
+  foo: MethodMember
+    base: self::@extensionType::A::@method::foo
+    substitution: {T: int}
+  it: self::@extensionType::B::@getter::it
+declared
+  it: self::@extensionType::B::@getter::it
+redeclared
+  foo
+    MethodMember
+      base: self::@extensionType::A::@method::foo
+      substitution: {T: int}
+  it
+    PropertyAccessorMember
+      base: self::@extensionType::A::@getter::it
+      substitution: {T: int}
+''');
+  }
+
   test_noDeclaration_implementExtensionType_method() async {
     final library = await buildLibrary(r'''
 extension type A(int it) {