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>
14 
15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16 #  pragma GCC system_header
17 #endif
18 
19 _LIBCPP_BEGIN_NAMESPACE_STD
20 
21 #if _LIBCPP_STD_VER > 17
22 
23 // Whether a type is a class type or enumeration type according to the Core wording.
24 
25 template<class _Tp>
26 concept __class_or_enum = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>;
27 
28 // Work around Clang bug https://llvm.org/PR52970
29 // TODO: remove this workaround once libc++ no longer has to support Clang 13 (it was fixed in Clang 14).
30 template<class _Tp>
31 concept __workaround_52970 = is_class_v<__uncvref_t<_Tp>> || is_union_v<__uncvref_t<_Tp>>;
32 
33 #endif // _LIBCPP_STD_VER > 17
34 
35 _LIBCPP_END_NAMESPACE_STD
36 
37 #endif // _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
38