| // Copyright (c) 2024, 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. | |
| extension type EINullable(int? _) implements int? {} // Error. | |
| class A {} | |
| class B implements A? {} // Error. | |
| typedef F<T> = T; | |
| extension type EIAliasNullable(A? _) implements F<A?> {} // Error. |