LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A15_t01.dart

/*
 * 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 A composite member invocation on a target expression X is an
 * expression of one of the forms:
 * Composite member invocation on target X	     Corresponding member base name
 *    X.id binop= expr2	                                       id
 * @description Check explicit extension member invocation in form of
 * X.id += expr2
 * @author sgrekhov@unipro.ru
 */

import "../../Utils/expect.dart";

class C {
  int value;
  C() : value = 0 {}
  init() {
    value = 0;
  }
  int get id => value;
  void set id(int v) {
    this.value = v;
  }
}

extension Extension1 on C {
  int get id => this.value + 1;
  void set id(int v) {
    this.value = v + 1;
  }
}

extension Extension2 on C {
  int get id => this.value + 2;
  void set id(int v) {
    this.value = v + 2;
  }
}

main() {
  C c = C();
  Extension1(c).id += 42;
  Expect.equals(44, c.value);
  c.init();
  Extension2(c).id += 42;
  Expect.equals(46, c.value);
  c.init();
  c.id += 42;
  Expect.equals(42, c.value);
}