// Copyright (c) 2016, 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 HashSet.identity()
/// Creates an unordered identity-based set.
/// Effectively a shorthand for:
/// new HashSet<E>(equals: identical, hashCode: identityHashCode)
/// @description Checks that created hash set is equivalent of
/// new HashSet<E>(equals: identical, hashCode: identityHashCode)
/// @author sgrekhov@unipro.ru

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

class C {
  int get hashCode => 1;
  bool operator ==(dynamic c) {
    return true;
  }
}

main() {
  HashSet<C> set1 = new HashSet<C>.identity();
  HashSet<C> set2 = new HashSet<C>(
      equals: identical, hashCode: identityHashCode);
  HashSet<C> set3 = new HashSet<C>();

  C val1 = new C();
  C val2 = new C();
  C val3 = new C();

  set1.add(val1);
  set1.add(val2);
  set1.add(val3);

  set2.add(val1);
  set2.add(val2);
  set2.add(val3);

  set3.add(val1);
  set3.add(val2);
  set3.add(val3);

  Expect.equals(3, set1.length);
  Expect.equals(3, set2.length);
  Expect.equals(1, set3.length);
}