| // Copyright (c) 2025, 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. | |
| class A1 {} | |
| extension A2 on A1 {} | |
| class B1<T> {} | |
| extension B2<T> on B1<T> {} | |
| extension B3 on B1<A1> {} | |
| extension B4<T extends A1> on B1<T> {} | |
| main() {} |