LanguageFeatures/FinalizationRegistry/ffi/WeakReference/weak_reference_target_t02.dart

// Copyright (c) 2022, 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 target property
/// T? target
/// The current object weakly referenced by this, if any.
///
/// The value is either the object supplied in the constructor, or null if the
/// weak reference has been cleared.
///
/// @description Check that the value of this property value is either the
/// object supplied in the constructor, or null if the weak reference has been
/// cleared
/// @author sgrekhov@unipro.ru
/// @issue 48391

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

class C {
  int id;
  C(this.id);

  String toString() => "C($id)";
}

@pragma('vm:never-inline')
WeakReference<C> createWeakReference() {
  List<C> refs = List.filled(5, C(42), growable: true);
  WeakReference<C>  wr = WeakReference(refs[0]);
  Expect.equals(refs[0], wr.target);
  triggerGc();
  Expect.equals(refs[1], wr.target);
  return wr;
}

main() {
  WeakReference<C> wr = createWeakReference();
  triggerGc();
  Expect.isNull(wr.target);
}