| /* |
| * 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 extension type parameter can also occur as a parameter type |
| * for the method. |
| * |
| * Example: |
| * |
| * extension TypedEquals<T> { |
| * bool equals(T value) => this == value; |
| * } |
| * |
| * Using such an extension as: |
| * |
| * Object o = ...; |
| * String s = ...; |
| * print(s.equals(o)); // Compile-time type error. |
| * |
| * will fail. While we could make it work by inferring [T] as [Object], we |
| * don't. We infer [T] only based on the receiver type, and therefore [T] is |
| * [String], and [o] is not a valid argument (at least not when we remove |
| * implicit downcasts). |
| * @description Check that compile time error is thrown when method type |
| * parameter is incorrect. |
| * @compile-error |
| * @author iarkh@unipro.ru |
| */ |
| // SharedOptions=--enable-experiment=extension-methods |
| |
| extension TypedEquals<T> on T { |
| bool equals(T value) => this == value; |
| } |
| |
| main() { |
| String s = "12345"; |
| bool b = s.equals(12); |
| } |
