//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <memory>

// UNSUPPORTED: c++03, c++11, c++14, c++17

// template <class T> constexpr T* to_address(T* p) noexcept;
// template <class Ptr> constexpr auto to_address(const Ptr& p) noexcept;

#include <memory>
#include <cassert>
#include "test_macros.h"

class P1
{
public:
    using element_type = int;

    constexpr explicit P1(int* p)
    : p_(p) { }

    constexpr int* operator->() const noexcept
    { return p_; }

private:
    int* p_;
};

class P2
{
public:
    using element_type = int;

    constexpr explicit P2(int* p)
    : p_(p) { }

    constexpr P1 operator->() const noexcept
    { return p_; }

private:
    P1 p_;
};

class P3
{
public:
    constexpr explicit P3(int* p)
    : p_(p) { }

    constexpr int* get() const noexcept
    { return p_; }

private:
    int* p_;
};

namespace std
{
template<>
struct pointer_traits<::P3>
{
    static constexpr int* to_address(const ::P3& p) noexcept
    { return p.get(); }
};
}

class P4
{
public:
    constexpr explicit P4(int* p)
    : p_(p) { }

    constexpr int* operator->() const noexcept
    { return nullptr; }

    constexpr int* get() const noexcept
    { return p_; }

private:
    int* p_;
};

namespace std
{
template<>
struct pointer_traits<::P4>
{
    constexpr static int* to_address(const ::P4& p) noexcept
    { return p.get(); }
};
}

int n = 0;
static_assert(std::to_address(&n) == &n);

constexpr bool test() {
  int i = 0;
  ASSERT_NOEXCEPT(std::to_address(&i));
  assert(std::to_address(&i) == &i);
  P1 p1(&i);
  ASSERT_NOEXCEPT(std::to_address(p1));
  assert(std::to_address(p1) == &i);
  P2 p2(&i);
  ASSERT_NOEXCEPT(std::to_address(p2));
  assert(std::to_address(p2) == &i);
  P3 p3(&i);
  ASSERT_NOEXCEPT(std::to_address(p3));
  assert(std::to_address(p3) == &i);
  P4 p4(&i);
  ASSERT_NOEXCEPT(std::to_address(p4));
  assert(std::to_address(p4) == &i);

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());
  return 0;
}