| // Copyright (c) 2011, 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. |
| |
| /// @assertion Unless explicitly stated otherwise, all ordinary rules that apply |
| /// to methods apply to abstract methods. |
| /// It is a compile error if an instance method m1 overrides an instance member |
| /// m2 and the type of m1 is not a subtype of the type of m2. |
| /// @description Checks that a compile error is produced when the type of an |
| /// abstract m1 is not a subtype of the non-abstract m2's type because their |
| /// respective optional positional parameter types are not mutually assignable. |
| /// @author rodionov |
| |
| |
| class A { |
| foo([int? x]) {} |
| } |
| |
| abstract class B extends A { |
| foo([String? x]); |
| // ^ |
| // [analyzer] unspecified |
| // [cfe] unspecified |
| } |
| |
| class C extends B { |
| foo([String? x]) {} |
| } |
| |
| main() { |
| new A().foo(2); |
| new C().foo("1"); |
| } |