Joe Loser d2baefae68
[libc++] Replace _LIBCPP_HAS_NO_CONCEPTS with _LIBCPP_STD_VER > 17. NFCI.
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.

Differential Revision: https://reviews.llvm.org/D121528
2022-03-13 12:32:06 -04:00

48 lines
1.3 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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___RANGES_ENABLE_VIEW_H
#define _LIBCPP___RANGES_ENABLE_VIEW_H
#include <__config>
#include <concepts>
#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
namespace ranges {
struct view_base { };
template<class _Derived>
requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
class view_interface;
template<class _Op, class _Yp>
requires is_convertible_v<_Op*, view_interface<_Yp>*>
void __is_derived_from_view_interface(const _Op*, const view_interface<_Yp>*);
template <class _Tp>
inline constexpr bool enable_view = derived_from<_Tp, view_base> ||
requires { ranges::__is_derived_from_view_interface((_Tp*)nullptr, (_Tp*)nullptr); };
} // namespace ranges
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___RANGES_ENABLE_VIEW_H