pkg/front_end/testcases/nnbd_mixed/flutter_issue_63029/flutter_issue_63029_lib1.dart

// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
// 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 {}

abstract class B<T extends A> {}