Language/Expressions/Assignment/Compound_Assignment/null_aware_indexed_assignment_t02.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 Evaluation of a compound assignment of the form e1[e2] ??= e3 is
 * equivalent to the evaluation of the expression
 * ((a, i) => ((x) => x == null ? a[i] = e3 : x)(a[i]))(e1, e2) where x, a and i
 * are distinct fresh variables that are not used in e3.
 * @description Checks that in expression of the form e1.[e2] ??= e3 value is
 * set only if e1[e2] == null. Test the case when part of e1 is prefix
 * @author sgrekhov@unipro.ru
 */

import '../../../../Utils/expect.dart';
import 'null_aware_assignment_lib.dart' as lib;

main() {
  lib.c1[1 - 1] ??= 1;
  Expect.equals(1, lib.c1.v1);

  lib.c1[1 + 1] ??= 2;
  Expect.equals(1, lib.c1.v1);
}