Language/Expressions/Instance_Creation/Const/canonicalized_t04.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 a fresh instance of an object is created
/// if any of the fields in i are not identical to the fields in j.
/// @author msyabro

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

class A {
  const A(p1): x = p1, y = 3;
  final x;
  final y;
}

main() {
  const o1 = const A(1);
  const o2 = const A(2);
  const CheckNotIdentical(o1, o2);

  const CheckIdentical(o1, const A(1));
  const CheckNotIdentical(const A(1), o2);
  const CheckIdentical(o2, const A(2));
  const CheckNotIdentical(const A(2), o1);
}