// 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.

// @dart = 2.9

/// @assertion It also enables const expressions that refer to constant
/// collections defined elsewhere, which is useful:
///   const list = [2, 3];
///   const another = [1, ...list, 4]; // [1, 2, 3, 4].
/// @description: Checks that spread element in the list can refer to constant
/// collections defined elsewhere
/// @author iarkh@unipro.ru


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

main() {
  const list = [2, 3];
  const list1 = null;
  const res1 = [1, ...list, 4];
  Expect.listEquals([1, 2, 3, 4], res1);
  const res2 = [1, ...?list, 4];
  Expect.listEquals([1, 2, 3, 4], res2);
  const res3 = [1, ...?list1, 4];
  Expect.listEquals([1, 4], res3);

  const set = {2, 3};
  const res4 = [1, ...set, 4];
  Expect.listEquals([1, 2, 3, 4], res4);
  const res5 = [1, ...?set, 4];
  Expect.listEquals([1, 2, 3, 4], res5);
}