anchor.diff:              message('/home/test/lib/test.dart', 92, 1)
             ]),
       ]);
  +  }
  +
  +  test_redirectingConstructor_optIn_fromOptOut_Null() async {
  +    newFile('$testPackageLibPath/a.dart', content: r'''
  +import 'test.dart';
  +
  +class A<X extends int> implements B {}
  +''');
  +
  +    await assertNoErrorsInCode(r'''
  +// @dart=2.6
  +import 'a.dart';
  +
  +class B {
  +  factory B() = A<Null>;
  +}
  +''');
     }
   
     test_regression_42196() async {
  
positive.code: ''');
    }
  
    test_metadata_matching() async {
      await assertNoErrorsInCode(r'''
  class A<T extends num> {
  
negative.code: ''', [
        error(CompileTimeErrorCode.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS, 131, 1),
      ]);
    }
  
    test_methodInvocation_optIn_fromOptOut_Null() async {
      newFile('$testPackageLibPath/a.dart', content: r'''
  class A {
    void m<X extends int>() {}
  ''');
  
      await assertNoErrorsInCode(r'''
  // @dart=2.6
  import 'a.dart';
  
  f() => A().m<Null>();
  ''');
    }
  
    test_nonFunctionTypeAlias_body_typeArgument_mismatch() async {
  