tests/language_2/const/set_hashcode_override2_test.dart

// Copyright (c) 2021, 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

import 'package:expect/expect.dart';

/// Returns its argument.
///
/// Prevents static optimizations and inlining.
getValueNonOptimized(x) {
  // DateTime.now() cannot be predicted statically, never equal to ASCII 42 '*'.
  if (new DateTime.now() == 42) return getValueNonOptimized(2);
  return x;
}

class MyClass {
  final int n;

  const MyClass(this.n);

  int get hashCode => super.hashCode + 1;
}

main() {
  const constInstance = MyClass(1);
  final nonConstInstance = MyClass(1);

  const constSet = {MyClass(1)};
  final nonConstSet = {constInstance};
  final nonConstSet2 = {nonConstInstance};

  // operator== is _not_ overridden, so instances are not equal.
  Expect.notEquals(constInstance, nonConstInstance);

  Expect.isTrue(constSet.contains(getValueNonOptimized(constInstance)));
  Expect.isFalse(constSet.contains(getValueNonOptimized(nonConstInstance)));
  Expect.isTrue(nonConstSet.contains(getValueNonOptimized(constInstance)));
  Expect.isFalse(nonConstSet.contains(getValueNonOptimized(nonConstInstance)));
  Expect.isFalse(nonConstSet2.contains(getValueNonOptimized(constInstance)));
  Expect.isTrue(nonConstSet2.contains(getValueNonOptimized(nonConstInstance)));
}