| // 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. |
| |
| class A {} |
| |
| class B extends A {} |
| |
| class C { |
| int operator [](A a) => 0; |
| void operator []=(B b, int o) {} |
| } |
| |
| class D { |
| int operator [](B b) => 0; |
| void operator []=(A a, int o) {} |
| } |
| |
| void main() { |
| A a = new B(); |
| C c = new C(); |
| D d = new D(); |
| c[a] += 1; |
| //^ |
| // [analyzer] COMPILE_TIME_ERROR.ARGUMENT_TYPE_NOT_ASSIGNABLE |
| // [cfe] A value of type 'A' can't be assigned to a variable of type 'B'. |
| d[a] += 1; |
| //^ |
| // [analyzer] COMPILE_TIME_ERROR.ARGUMENT_TYPE_NOT_ASSIGNABLE |
| // [cfe] A value of type 'A' can't be assigned to a variable of type 'B'. |
| } |