| // Copyright (c) 2017, 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. |
| |
| // @dart = 2.9 |
| |
| abstract class F<T> { |
| T foo(T t); |
| } |
| |
| class B<T extends F<T>> {} |
| |
| class C<T extends F<C<T>>> {} |
| |
| class D extends B<D> implements F<D> { |
| D foo(D x) => x; |
| } |
| |
| class E extends C<E> implements F<C<E>> { |
| C<E> foo(C<E> x) => x; |
| } |
| |
| main() { |
| D fd = D(); |
| var d = fd.foo(fd); |
| print(d); |
| E fe = E(); |
| var e = fe.foo(fe); |
| print(e); |
| } |
