| // Copyright (c) 2019, 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 |
| |
| class A { |
| bool operator ==(other); |
| const A(); |
| } |
| |
| class B implements A { |
| const B(); |
| } |
| |
| class C extends A { |
| const C(); |
| } |
| |
| class Invalid { |
| bool operator ==(other) => false; |
| const Invalid(); |
| } |
| |
| class D implements Invalid { |
| const D(); |
| } |
| |
| main() { |
| print(const {A(): 1}); |
| print(const {B(): 2}); |
| print(const {C(): 3}); |
| print(const {D(): 4}); |
| } |