// 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 The [==] operator in constant expressions was defined such that
/// [e1 != null] was only allowed if [e1] had one of the "primitive" system
/// types. Users had to rewrite their code to [!identical(e1, null)]. This was
/// changed so that the [==] expression is always allowed as long as one of the
/// operands is [null].
/// @description Checks that [==] operator is allowed if one of the operands is
/// [null] in potentially constant or compile-time constant, and compile time
/// error is thrown if assertion fails.
/// @author iarkh@unipro.ru


const str1 = "test";
const str2 = null;

class MyClass {
  final String option;
  const MyClass(String str) : assert(str == null), this.option = "OK";
}

main() {
  const MyClass c1 = MyClass("123");
//                   ^
// [analyzer] unspecified
// [cfe] unspecified
}