Language/12_Expressions/12_Instance_Creation/2_Const_A08_t03.dart

/*
 * Copyright (c) 2011, 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 e proceeds as follows:
 * First, if e is of the form const T.id(a1, .., an, xn+1: an+1, …, xn+k: an+k)
 * then let i be the value of the expression new T.id(a1, .., an, xn+1: an+1, …, xn+k: an+k).
 * Otherwise, e must be of the form  const T(a1, .., an, xn+1: an+1, …, xn+k: an+k),
 * in which case let i be the result of evaluating new T(a1, .., an, xn+1: an+1, …, xn+k: an+k) .
 * Then:
 * - If during execution of the program, a constant object expression has already evaluated
 *   to an instance j of class R with type arguments Vi , 1<=i<=m, then:
 *    – For each instance variable f of i, let vif be the value of the field f in
 *      i, and let vjf be the value of the field f in j. If identical(vif , vjf ) for
 *      all fields f in i, then the value of e is j, otherwise the value of e is i.
 * - Otherwise the value of e is i.
 * In other words, constant objects are canonicalized.
 * @description Checks that constant object expressions yield identical objects if
 * all fields in constructed instances are identical.
 * @author msyabro
 * @reviewer rodionov
 */
import "../../../Utils/expect.dart";

class A {
  const A(): x = 1;
  final x;
}

class B {
  const B(arg): foo = arg;
  final foo;
}

main() {
  var o = const A();
  for(int i = 0; i < 10; i++) {
    Expect.identical(o, const A());
  }

  Expect.identical(const B(const Object()), const B(const Object()));
}