| /* |
| * 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. |
| */ |
| /** |
| * @assertion The grammar of selectors is extended to allow null-aware |
| * subscripting using the syntax e1?.[e2] which evaluates to null if e1 |
| * evaluates to null and otherwise evaluates as e1[e2]. |
| * |
| * @description Check that the grammar of selectors is extended to allow |
| * null-aware subscripting using the syntax e1?.[e2] which evaluates to null if |
| * e1 evaluates to null and otherwise evaluates as e1[e2]. Test type aliases |
| * @author sgrekhov@unipro.ru |
| */ |
| // SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases |
| import "../../Utils/expect.dart"; |
| |
| class C { |
| int operator[](int index) => index * 2; |
| } |
| |
| typedef CAlias = C?; |
| |
| main() { |
| CAlias c = null; |
| Expect.isNull(c?.[42]); |
| c = new C(); |
| Expect.equals(4, c?.[2]); |
| } |