1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___TYPE_TRAITS_IS_SPECIALIZATION
11 #define _LIBCPP___TYPE_TRAITS_IS_SPECIALIZATION
12 
13 // This contains parts of P2098R1 but is based on MSVC STL's implementation.
14 //
15 // The paper has been rejected
16 //   We will not pursue P2098R0 (std::is_specialization_of) at this time; we'd
17 //   like to see a solution to this problem, but it requires language evolution
18 //   too.
19 //
20 // Since it is expected a real solution will be provided in the future only the
21 // minimal part is implemented.
22 //
23 // Note a cvref qualified _Tp is never considered a specialization.
24 
25 #include <__config>
26 
27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28 #  pragma GCC system_header
29 #endif
30 
31 _LIBCPP_BEGIN_NAMESPACE_STD
32 
33 #if _LIBCPP_STD_VER > 14
34 
35 template <class _Tp, template <class...> class _Template>
36 inline constexpr bool __is_specialization_v = false; // true if and only if _Tp is a specialization of _Template
37 
38 template <template <class...> class _Template, class... _Args>
39 inline constexpr bool __is_specialization_v<_Template<_Args...>, _Template> = true;
40 
41 #endif // _LIBCPP_STD_VER > 14
42 
43 _LIBCPP_END_NAMESPACE_STD
44 
45 #endif // _LIBCPP___TYPE_TRAITS_IS_SPECIALIZATION
46