// Copyright (c) 2021, 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.

import 'package:expect/expect.dart';

void main() {
  var v = {
    ...Map.unmodifiable({'x': null})
  };
  Expect.equals(null, v['x']);
}