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___ITERATOR_CONCEPTS_H
11 #define _LIBCPP___ITERATOR_CONCEPTS_H
12 
13 #include <__config>
14 #include <concepts>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #pragma GCC system_header
18 #endif
19 
20 _LIBCPP_PUSH_MACROS
21 #include <__undef_macros>
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 #if !defined(_LIBCPP_HAS_NO_RANGES)
26 
27 template<class _Tp>
28 using __with_reference = _Tp&;
29 
30 template<class _Tp>
31 concept __referenceable = requires {
32   typename __with_reference<_Tp>;
33 };
34 
35 template<class _Tp>
36 concept __dereferenceable = requires(_Tp& __t) {
37   { *__t } -> __referenceable; // not required to be equality-preserving
38 };
39 
40 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
41 
42 _LIBCPP_END_NAMESPACE_STD
43 
44 _LIBCPP_POP_MACROS
45 
46 #endif // _LIBCPP___ITERATOR_CONCEPTS_H
47