text: // -*- 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___ITERATOR_ITER_MOVE_H
  #define _LIBCPP___ITERATOR_ITER_MOVE_H
  
  #include <__concepts/class_or_enum.h>
  #include <__config>
  #include <__iterator/iterator_traits.h>
  #include <__utility/forward.h>
  #include <__utility/move.h>
  #include <type_traits>
  
  #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  #  pragma GCC system_header
  #endif
  
  _LIBCPP_BEGIN_NAMESPACE_STD
  
  #if !defined(_LIBCPP_HAS_NO_CONCEPTS)
  
  // [iterator.cust.move]
  
  namespace ranges {
  namespace __iter_move {
  
  void iter_move();
  
  template <class _Tp>
  concept __unqualified_iter_move =
    __class_or_enum<remove_cvref_t<_Tp>> &&
    requires (_Tp&& __t) {
      iter_move(std::forward<_Tp>(__t));
    };
  
  template<class _Tp>
  concept __move_deref =
    !__unqualified_iter_move<_Tp> &&
    requires (_Tp&& __t) {
      *__t;
      requires is_lvalue_reference_v<decltype(*__t)>;
    };
  
  template<class _Tp>
  concept __just_deref =
    !__unqualified_iter_move<_Tp> &&
    !__move_deref<_Tp> &&
    requires (_Tp&& __t) {
      *__t;
      requires (!is_lvalue_reference_v<decltype(*__t)>);
    };
  
  // [iterator.cust.move]
  
  struct __fn {
    template<class _Ip>
      requires __unqualified_iter_move<_Ip>
    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const
      noexcept(noexcept(iter_move(std::forward<_Ip>(__i))))
    {
      return iter_move(std::forward<_Ip>(__i));
    }
  
    template<class _Ip>
      requires __move_deref<_Ip>
    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const
      noexcept(noexcept(std::move(*std::forward<_Ip>(__i))))
      -> decltype(      std::move(*std::forward<_Ip>(__i)))
      { return          std::move(*std::forward<_Ip>(__i)); }
  
    template<class _Ip>
      requires __just_deref<_Ip>
    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const
      noexcept(noexcept(*std::forward<_Ip>(__i)))
      -> decltype(      *std::forward<_Ip>(__i))
      { return          *std::forward<_Ip>(__i); }
  };
  } // namespace __iter_move
  
  inline namespace __cpo {
    inline constexpr auto iter_move = __iter_move::__fn{};
  } // namespace __cpo
  } // namespace ranges
  
  template<__dereferenceable _Tp>
    requires requires(_Tp& __t) { { ranges::iter_move(__t) } -> __can_reference; }
  using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<_Tp&>()));
  
  #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
  
  _LIBCPP_END_NAMESPACE_STD
  
  #endif // _LIBCPP___ITERATOR_ITER_MOVE_H
  