llvm-project/libcxx/include/__concepts/derived_from.h

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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___CONCEPTS_DERIVED_FROM_H
#define _LIBCPP___CONCEPTS_DERIVED_FROM_H
#include <__config>
#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.derived]
template<class _Dp, class _Bp>
concept derived_from =
is_base_of_v<_Bp, _Dp> &&
is_convertible_v<const volatile _Dp*, const volatile _Bp*>;
#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___CONCEPTS_DERIVED_FROM_H