LanguageFeatures/Super-bounded-types/motivation_example_A01_t01.dart

// Copyright (c) 2018, 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.

// @dart = 2.9

/// @assertion
/// Here are some examples of finite unfoldings, and the effect they have on
/// types of expressions:
/// c0.next.unknown(42); // Statically OK, `c0.next` is `dynamic`.
/// @description Checks that [c0.next.unknown(42)] line from the test example is
/// statically OK and causes [NoSuchMethodError] in runtime.
/// @author iarkh@unipro.ru
/// @issue #32903

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

class C<X extends C<X>> {
  X next;
  C(this.next);
}

class D extends C<D> {
  D(D next): super(next);
}

main() {
  D d = new D(new D(null));
  C<dynamic> c0 = d;
  Expect.throws(() { c0.next.unknown(42); }, (e) => e is NoSuchMethodError);
}