Language/Reference/Operator_Precedence/precedence_05_logical_or_t01.dart

// 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.

/// @assertion
/// Description    Operator                          Associativity Precedence
/// Logical OR        ||                                Left           5
/// @description Test that '||' logical OR operator has precedence (5).
/// Compare with if-null '??' operator (precedence 4). Test that '||' has
/// priority higher than '??'
/// @author sgrekhov@unipro.ru

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

String log = "";

class C {
  bool m(String val) {
    log += val;
    return false;
  }
}

main() {
  dynamic c = new C();
  c.m("c1") || c.m("c2") ?? c.m("c3") || c.m("c4");
//                          ^^^^^^^^^^^^^^^^^^^^^^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
//          ^
// [cfe] Operand of null-aware operation '??' has type 'bool' which excludes null.
  Expect.equals("c1c2", log);

  log = "";

  null ?? c.m("c3") || c.m("c4");
  Expect.equals("c3c4", log);
}