| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___CONCEPTS_ASSIGNABLE_H |
| #define _LIBCPP___CONCEPTS_ASSIGNABLE_H |
| |
| #include <__concepts/common_reference_with.h> |
| #include <__concepts/same_as.h> |
| #include <__config> |
| #include <__utility/forward.h> |
| #include <type_traits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| // [concept.assignable] |
| |
| template<class _Lhs, class _Rhs> |
| concept assignable_from = |
| is_lvalue_reference_v<_Lhs> && |
| common_reference_with<__make_const_lvalue_ref<_Lhs>, __make_const_lvalue_ref<_Rhs>> && |
| requires (_Lhs __lhs, _Rhs&& __rhs) { |
| { __lhs = _VSTD::forward<_Rhs>(__rhs) } -> same_as<_Lhs>; |
| }; |
| |
| #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___CONCEPTS_ASSIGNABLE_H |
