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//===----------------------------------------------------------------------===//
//
// 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___CXX03___CONCEPTS_ASSIGNABLE_H
#define _LIBCPP___CXX03___CONCEPTS_ASSIGNABLE_H
#include <__cxx03/__concepts/common_reference_with.h>
#include <__cxx03/__concepts/same_as.h>
#include <__cxx03/__config>
#include <__cxx03/__type_traits/is_reference.h>
#include <__cxx03/__type_traits/make_const_lvalue_ref.h>
#include <__cxx03/__utility/forward.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
// [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 = std::forward<_Rhs>(__rhs) } -> same_as<_Lhs>;
};
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___CXX03___CONCEPTS_ASSIGNABLE_H
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