//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++98, c++03, c++11

// <propagate_const>

// template <class T> constexpr bool operator==(const propagate_const<T>& x, const propagate_const<T>& y);
// template <class T> constexpr bool operator==(const T& x, const propagate_const<T>& y);
// template <class T> constexpr bool operator==(const propagate_const<T>& x, const T& y);

#include <experimental/propagate_const>
#include "propagate_const_helpers.h"
#include <cassert>

using std::experimental::propagate_const;
using std::nullptr_t;

constexpr bool operator==(const X &lhs, const X &rhs) {
  return lhs.i_ == rhs.i_;
}

constexpr bool operator==(const X &, const nullptr_t &) {
  return false;
}

constexpr bool operator==(const nullptr_t &, const X &) {
  return false;
}

int main() {
  constexpr X x1_1(1);
  constexpr X x2_1(1);
  constexpr X x3_2(2);

  static_assert(x1_1 == x1_1, "");
  static_assert(x1_1 == x2_1, "");
  static_assert(!(x1_1 == x3_2), "");

  typedef propagate_const<X> P;

  constexpr P p1_1(1);
  constexpr P p2_1(1);
  constexpr P p3_2(2);

  static_assert(p1_1 == p1_1, "");
  static_assert(p1_1 == p2_1, "");
  static_assert(!(p1_1 == p3_2), "");

  static_assert(x1_1 == p1_1, "");
  static_assert(!(x1_1 == p3_2), "");

  static_assert(p1_1 == x1_1, "");
  static_assert(!(p1_1 == x3_2), "");

  static_assert(!(p1_1==nullptr),"");
  static_assert(!(nullptr==p1_1),"");
}