Language/Expressions/If_null_Expressions/static_type_t02.dart

// Copyright (c) 2015, 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 Evaluation of an if-null expression e of the form e1??e2 is
/// equivalent ... The static type of e is least upper bound of the
/// static type of e1 and the static type of e2 .
///
/// @description Check that static type of expression e1 ?? e2 is least upper
/// bound of the static type of e1 and the static type of e2 .
///
/// @author a.semenov@unipro.ru
/// @author sgrekhov@unipro.ru
///

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

main() {
  var x1 = 1.0 ?? 2.0;
  Expect.isTrue(x1 is double);

  var x2 = null ?? 2.0;
  Expect.isTrue(x2 is double);

  var x3 = 'aaa' ?? 'bbb';
  Expect.isTrue(x3 is String);

  var x4 = true ?? false;
  Expect.isTrue(x4 is bool);

  var x5 = new LinkedHashMap() ?? new SplayTreeMap();
  Expect.isTrue(x5 is LinkedHashMap);

  var x6 = 'aaa' ?? null;
  Expect.isTrue(x6 is String);
}