//===----------------------------------------------------------------------===//
//
// 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___CONCEPTS_BOOLEAN_TESTABLE_H
#define _LIBCUDACXX___CONCEPTS_BOOLEAN_TESTABLE_H

#include <cuda/std/detail/__config>

#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 <cuda/std/__concepts/concept_macros.h>
#include <cuda/std/__concepts/convertible_to.h>
#include <cuda/std/__utility/forward.h>

_LIBCUDACXX_BEGIN_NAMESPACE_STD

#if !defined(_CCCL_NO_CONCEPTS)

// [concepts.booleantestable]

template <class _Tp>
concept __boolean_testable_impl = convertible_to<_Tp, bool>;

template <class _Tp>
concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
  { !_CUDA_VSTD::forward<_Tp>(__t) } -> __boolean_testable_impl;
};

#elif !defined(_CCCL_NO_VARIABLE_TEMPLATES) // ^^^ !_CCCL_NO_CONCEPTS ^^^

template <class _Tp>
_CCCL_CONCEPT __boolean_testable_impl = convertible_to<_Tp, bool>;

template <class _Tp>
_CCCL_CONCEPT_FRAGMENT(
  __boolean_testable_,
  requires(_Tp&& __t)(requires(__boolean_testable_impl<_Tp>),
                      requires(__boolean_testable_impl<decltype(!_CUDA_VSTD::forward<_Tp>(__t))>)));

template <class _Tp>
_CCCL_CONCEPT __boolean_testable = _CCCL_FRAGMENT(__boolean_testable_, _Tp);

#endif // ^^^ !_CCCL_NO_VARIABLE_TEMPLATES

_LIBCUDACXX_END_NAMESPACE_STD

#endif // _LIBCUDACXX___CONCEPTS_BOOLEAN_TESTABLE_H
