anchor.diff:  main() {
     defineReflectiveSuite(() {
       defineReflectiveTests(ExtensionMethodsDeclarationTest);
  +    defineReflectiveTests(ExtensionMethodsExtendedTypeTest);
       defineReflectiveTests(ExtensionMethodsExternalReferenceTest);
       defineReflectiveTests(ExtensionMethodsInternalReferenceTest);
     });
  
positive.code:     assertType(extendedType, 'C');
    }
  
    test_unnamed_generic() async {
      await assertNoErrorsInCode('''
  class C<T> {}
  
negative.code:     assertType(extendedType, 'C');
    }
  
    test_unnamed_onMixin() async {
      await assertNoErrorsInCode('''
  mixin M {
  }
  extension on M {}
  ''');
      var extendedType = findNode.typeAnnotation('M {}');
      assertElement(extendedType, findElement.mixin('M'));
      assertType(extendedType, 'M');
    }
  }
  
  