Language/Classes/Superinterfaces/syntax_t03.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 class has a set of direct superinterfaces. This set includes
 * the interface of its superclass and the interfaces specified in the the
 * implements clause of the class.
 * interfaces:
 *   implements typeList
 * ;
 * @description Checks that a class can indeed specify one or more
 * superinterfaces using the implements clause and an instance of this class
 * will also be an instance of those interfaces as well as any and all of its
 * superclasses' superinterfaces.
 * @author sgrekhov@unipro.ru
 */
// SharedOptions=--enable-experiment=nonfunction-type-aliases

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

abstract class IA {}
typedef IAAlias = IA;
class A implements IAAlias {}
abstract class IB {}
typedef IBAlias = IB;
class B extends IAAlias implements IBAlias {}
abstract class IC {}
typedef ICAlias = IC;
abstract class ID {}
typedef IDAlias = ID;
class C extends B implements ICAlias, IDAlias {}

main() {
  C c = new C();
  Expect.isTrue(c is IA);
  Expect.isTrue(c is IB);
  Expect.isTrue(c is IC);
  Expect.isTrue(c is ID);
}