common_reference_with.h 1.1 KB

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  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. #ifndef _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
  9. #define _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
  10. #include <__concepts/convertible_to.h>
  11. #include <__concepts/same_as.h>
  12. #include <__config>
  13. #include <__type_traits/common_reference.h>
  14. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  15. # pragma GCC system_header
  16. #endif
  17. _LIBCPP_BEGIN_NAMESPACE_STD
  18. #if _LIBCPP_STD_VER >= 20
  19. // [concept.commonref]
  20. template <class _Tp, class _Up>
  21. concept common_reference_with =
  22. same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> &&
  23. convertible_to<_Tp, common_reference_t<_Tp, _Up>> && convertible_to<_Up, common_reference_t<_Tp, _Up>>;
  24. #endif // _LIBCPP_STD_VER >= 20
  25. _LIBCPP_END_NAMESPACE_STD
  26. #endif // _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H