libcxx/include/__concepts/class_or_enum.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
  10 #define _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
  11
  12 #include <__config>
  13 #include <__type_traits/is_class.h>
  14 #include <__type_traits/is_enum.h>
  15 #include <__type_traits/is_union.h>
  16 #include <__type_traits/remove_cvref.h>
  17
  18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  19 #  pragma GCC system_header
  20 #endif
  21
  22 _LIBCPP_BEGIN_NAMESPACE_STD
  23
  24 #if _LIBCPP_STD_VER >= 20
  25
  26 // Whether a type is a class type or enumeration type according to the Core wording.
  27
  28 template <class _Tp>
  29 concept __class_or_enum = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>;
  30
  31 // Work around Clang bug https://llvm.org/PR52970
  32 // TODO: remove this workaround once libc++ no longer has to support Clang 13 (it was fixed in Clang 14).
  33 template <class _Tp>
  34 concept __workaround_52970 = is_class_v<__remove_cvref_t<_Tp>> || is_union_v<__remove_cvref_t<_Tp>>;
  35
  36 #endif // _LIBCPP_STD_VER >= 20
  37
  38 _LIBCPP_END_NAMESPACE_STD
  39
  40 #endif // _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H