convertible_to.h 981 B

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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_CONVERTIBLE_TO_H
  9. #define _LIBCPP___CONCEPTS_CONVERTIBLE_TO_H
  10. #include <__config>
  11. #include <__type_traits/is_convertible.h>
  12. #include <__utility/declval.h>
  13. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  14. # pragma GCC system_header
  15. #endif
  16. _LIBCPP_BEGIN_NAMESPACE_STD
  17. #if _LIBCPP_STD_VER > 17
  18. // [concept.convertible]
  19. template<class _From, class _To>
  20. concept convertible_to =
  21. is_convertible_v<_From, _To> &&
  22. requires {
  23. static_cast<_To>(std::declval<_From>());
  24. };
  25. #endif // _LIBCPP_STD_VER > 17
  26. _LIBCPP_END_NAMESPACE_STD
  27. #endif // _LIBCPP___CONCEPTS_CONVERTIBLE_TO_H