// 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 If f is marked sync*, then a fresh instance i implementing
/// the built-in class Iterable is associated with the invocation and
/// immediately returned.
///    A Dart implementation will need to provide a specific implementation of
///  Iterable that will be returned by sync* methods. A typical strategy would
///  be to produce an instance of a subclass of class IterableBase defined in
///  dart:core. The only method that needs to be added by the Dart
///  implementation in that case is iterator.
///
/// @description Check that a fresh instance of Iterable is returned to the
/// caller of sync generator.
///
/// @author a.semenov@unipro.ru


import '../../../Utils/expect.dart';

Iterable test() sync* {
  yield 1;
}

main() {
  Set history = new Set.identity();
  for (var i = 0; i < 10; i++) {
    Iterable s = test();
    Expect.isFalse(history.contains(s));
    history.add(s);
  }
}