//===----------------------------------------------------------------------===//
//
// 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
// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCUDACXX___TYPE_TRAITS_IS_CORE_CONVERTIBLE_H
#define _LIBCUDACXX___TYPE_TRAITS_IS_CORE_CONVERTIBLE_H

#ifndef __cuda_std__
#include <__config>
#endif // __cuda_std__

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include "../__type_traits/integral_constant.h"

_LIBCUDACXX_BEGIN_NAMESPACE_STD

// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
// We can't test for that, but we can test implicit convertibility by passing it
// to a function. Notice that __is_core_convertible<void,void> is false,
// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.

template <class _Tp, class _Up, class = void>
struct __is_core_convertible : public false_type {};

template <class _Tp, class _Up>
struct __is_core_convertible<_Tp, _Up, decltype(
    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
)> : public true_type {};

_LIBCUDACXX_END_NAMESPACE_STD

#endif // _LIBCUDACXX___TYPE_TRAITS_IS_CORE_CONVERTIBLE_H
