Language/Expressions/Assignment/Compound_Assignment/null_aware_compound_assignment_t12.dart

// 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.

/**
 * @assertion Evaluation of a compound assignment of the form e1?.v op = e2 is
 * equivalent to ((x) => x?.v = x.v op e2)(e1) where x is a variable that is not
 * used in e2.
 * @description Checks that an expression of the form e1?.v >>>= e2 is
 * equivalent to ((x) => x?.v = x.v >>> e2)(e1) where x is a variable that is
 * not used in e2
 * @static-warning
 * @author iarkh@unipro.ru
 */
// SharedOptions=--enable-experiment=triple-shift

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

class C {
  int? _v;
  int getterInvocation = 0;
  int setterInvocation = 0;

  C(val) {
    _v = val;
  }

  get v {
    ++getterInvocation;
    return _v;
  }

  set v(val) {
    ++setterInvocation;
    _v = val;
  }
}

main() {
  C? c1 = null;
  var res1 = (c1?.v >>>= 2);
  Expect.isNull(res1);
  Expect.isNull(c1);

  C c2 = new C(null);
  Expect.throws(() {c2?.v >>>= 2;});      /// static type warning

  C c3 = new C(20);
  var res3 = (c3?.v >>>= 2);              /// static type warning
  var expected = 20 >>> 2;
  Expect.equals(1, c3.getterInvocation);
  Expect.equals(1, c3.setterInvocation);
  Expect.equals(expected, res3);
  Expect.equals(expected, c3.v);
}