libcxx/include/__type_traits/is_scoped_enum.h

//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___TYPE_TRAITS_IS_SCOPED_ENUM_H
#define _LIBCPP___TYPE_TRAITS_IS_SCOPED_ENUM_H

#include <__config>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_enum.h>
#include <__type_traits/underlying_type.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER >= 23

// TODO: GCC and Clang both have this builtin. Remove the false case once we've updated to GCC 14.
#  if __has_builtin(__is_scoped_enum)

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_scoped_enum : bool_constant<__is_scoped_enum(_Tp)> {};

template <class _Tp>
inline constexpr bool is_scoped_enum_v = __is_scoped_enum(_Tp);

#  else

template <class _Tp, bool = is_enum_v<_Tp> >
struct __is_scoped_enum_helper : false_type {};

template <class _Tp>
struct __is_scoped_enum_helper<_Tp, true> : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_scoped_enum : public __is_scoped_enum_helper<_Tp> {};

template <class _Tp>
inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;

#  endif // __has_builtin(__is_scoped_enum)

#endif // _LIBCPP_STD_VER >= 23

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___TYPE_TRAITS_IS_SCOPED_ENUM_H