| // Copyright (c) 2023, 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 E1(Never foo) {} // Error. | |
| extension type E2<X extends Never>(X foo) {} // Error. | |
| extension type E3<X extends Y, Y extends Never>(X foo) {} // Error. |