| // Copyright (c) 2018, 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 |
| |
| /// @assertion |
| /// Here are some examples of finite unfoldings, and the effect they have on |
| /// types of expressions: |
| /// d.next.next.next.next.next.next.next.unknown(46); // Compile-time error. |
| /// @description Checks that [d.next.next.next.next.next.next.next.unknown(46)] |
| /// line from the test example causes compile-time error and throws error in |
| /// runtime |
| /// @author iarkh@unipro.ru |
| |
| import "../../Utils/expect.dart"; |
| |
| class C<X extends C<X>> { |
| X next; |
| C(this.next); |
| } |
| |
| class D extends C<D> { |
| D(D next): super(next); |
| } |
| |
| main() { |
| D d = new D(new D(null)); |
| // With type `D`, the static analysis is aware of the cyclic |
| // structure of the type, and every level of nesting is handled |
| // safely. But `D` may be less useful because there may be a |
| // similar type `D2`, and this code will only work with `D`. |
| Expect.throws(() { |
| d.next.next.next.next.next.next.next.unknown(46); // Compile-time error. |
| // ^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| }); |
| } |