include/array

// -*- 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_ARRAY
#define _LIBCPP_ARRAY

/*
    array synopsis

namespace std
{
template <class T, size_t N >
struct array
{
    // types:
    typedef T & reference;
    typedef const T & const_reference;
    typedef implementation defined iterator;
    typedef implementation defined const_iterator;
    typedef size_t size_type;
    typedef ptrdiff_t difference_type;
    typedef T value_type;
    typedef T* pointer;
    typedef const T* const_pointer;
    typedef std::reverse_iterator<iterator> reverse_iterator;
    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

    // No explicit construct/copy/destroy for aggregate type
    void fill(const T& u);                                      // constexpr in C++20
    void swap(array& a) noexcept(is_nothrow_swappable_v<T>);    // constexpr in C++20

    // iterators:
    iterator begin() noexcept;                                  // constexpr in C++17
    const_iterator begin() const noexcept;                      // constexpr in C++17
    iterator end() noexcept;                                    // constexpr in C++17
    const_iterator end() const noexcept;                        // constexpr in C++17

    reverse_iterator rbegin() noexcept;                         // constexpr in C++17
    const_reverse_iterator rbegin() const noexcept;             // constexpr in C++17
    reverse_iterator rend() noexcept;                           // constexpr in C++17
    const_reverse_iterator rend() const noexcept;               // constexpr in C++17

    const_iterator cbegin() const noexcept;                     // constexpr in C++17
    const_iterator cend() const noexcept;                       // constexpr in C++17
    const_reverse_iterator crbegin() const noexcept;            // constexpr in C++17
    const_reverse_iterator crend() const noexcept;              // constexpr in C++17

    // capacity:
    constexpr size_type size() const noexcept;
    constexpr size_type max_size() const noexcept;
    constexpr bool empty() const noexcept;

    // element access:
    reference operator[](size_type n);                          // constexpr in C++17
    const_reference operator[](size_type n) const;              // constexpr in C++14
    reference at(size_type n);                                  // constexpr in C++17
    const_reference at(size_type n) const;                      // constexpr in C++14

    reference front();                                          // constexpr in C++17
    const_reference front() const;                              // constexpr in C++14
    reference back();                                           // constexpr in C++17
    const_reference back() const;                               // constexpr in C++14

    T* data() noexcept;                                         // constexpr in C++17
    const T* data() const noexcept;                             // constexpr in C++17
};

template <class T, class... U>
  array(T, U...) -> array<T, 1 + sizeof...(U)>;                 // C++17

template <class T, size_t N>
  bool operator==(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
template <class T, size_t N>
  bool operator!=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
template <class T, size_t N>
  bool operator<(const array<T,N>& x, const array<T,N>& y);     // constexpr in C++20
template <class T, size_t N>
  bool operator>(const array<T,N>& x, const array<T,N>& y);     // constexpr in C++20
template <class T, size_t N>
  bool operator<=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
template <class T, size_t N>
  bool operator>=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20

template <class T, size_t N >
  void swap(array<T,N>& x, array<T,N>& y) noexcept(noexcept(x.swap(y))); // constexpr in C++20

template <class T, size_t N>
  constexpr array<remove_cv_t<T>, N> to_array(T (&a)[N]);  // C++20
template <class T, size_t N>
  constexpr array<remove_cv_t<T>, N> to_array(T (&&a)[N]); // C++20

template <class T> struct tuple_size;
template <size_t I, class T> struct tuple_element;
template <class T, size_t N> struct tuple_size<array<T, N>>;
template <size_t I, class T, size_t N> struct tuple_element<I, array<T, N>>;
template <size_t I, class T, size_t N> T& get(array<T, N>&) noexcept;               // constexpr in C++14
template <size_t I, class T, size_t N> const T& get(const array<T, N>&) noexcept;   // constexpr in C++14
template <size_t I, class T, size_t N> T&& get(array<T, N>&&) noexcept;             // constexpr in C++14
template <size_t I, class T, size_t N> const T&& get(const array<T, N>&&) noexcept; // constexpr in C++14

}  // std

*/

#include <__algorithm/equal.h>
#include <__algorithm/fill_n.h>
#include <__algorithm/lexicographical_compare.h>
#include <__algorithm/swap_ranges.h>
#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <__iterator/reverse_iterator.h>
#include <__tuple>
#include <__utility/integer_sequence.h>
#include <__utility/move.h>
#include <__utility/unreachable.h>
#include <compare>
#include <stdexcept>
#include <type_traits>
#include <version>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp, size_t _Size>
struct _LIBCPP_TEMPLATE_VIS array
{
    // types:
    typedef array __self;
    typedef _Tp                                   value_type;
    typedef value_type&                           reference;
    typedef const value_type&                     const_reference;
    typedef value_type*                           iterator;
    typedef const value_type*                     const_iterator;
    typedef value_type*                           pointer;
    typedef const value_type*                     const_pointer;
    typedef size_t                                size_type;
    typedef ptrdiff_t                             difference_type;
    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;

    _Tp __elems_[_Size];

    // No explicit construct/copy/destroy for aggregate type
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    void fill(const value_type& __u) {
        _VSTD::fill_n(data(), _Size, __u);
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    void swap(array& __a) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
        _VSTD::swap_ranges(data(), data() + _Size, __a.data());
    }

    // iterators:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    iterator begin() _NOEXCEPT {return iterator(data());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator begin() const _NOEXCEPT {return const_iterator(data());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    iterator end() _NOEXCEPT {return iterator(data() + _Size);}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator end() const _NOEXCEPT {return const_iterator(data() + _Size);}

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator rbegin() const _NOEXCEPT {return const_reverse_iterator(end());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator rend() const _NOEXCEPT {return const_reverse_iterator(begin());}

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator cbegin() const _NOEXCEPT {return begin();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator cend() const _NOEXCEPT {return end();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator crend() const _NOEXCEPT {return rend();}

    // capacity:
    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT {return _Size;}
    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT {return _Size;}
    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {return _Size == 0;}

    // element access:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference operator[](size_type __n) _NOEXCEPT {
        _LIBCPP_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
        return __elems_[__n];
    }
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
    const_reference operator[](size_type __n) const _NOEXCEPT {
        _LIBCPP_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
        return __elems_[__n];
    }

    _LIBCPP_CONSTEXPR_AFTER_CXX14 reference at(size_type __n)
    {
        if (__n >= _Size)
            __throw_out_of_range("array::at");
        return __elems_[__n];
    }

    _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const
    {
        if (__n >= _Size)
            __throw_out_of_range("array::at");
        return __elems_[__n];
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference front()             _NOEXCEPT {return (*this)[0];}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference front() const _NOEXCEPT {return (*this)[0];}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference back()              _NOEXCEPT {return (*this)[_Size - 1];}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference back() const  _NOEXCEPT {return (*this)[_Size - 1];}

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    value_type* data() _NOEXCEPT {return __elems_;}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const value_type* data() const _NOEXCEPT {return __elems_;}
};

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS array<_Tp, 0>
{
    // types:
    typedef array __self;
    typedef _Tp                                   value_type;
    typedef value_type&                           reference;
    typedef const value_type&                     const_reference;
    typedef value_type*                           iterator;
    typedef const value_type*                     const_iterator;
    typedef value_type*                           pointer;
    typedef const value_type*                     const_pointer;
    typedef size_t                                size_type;
    typedef ptrdiff_t                             difference_type;
    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;

    typedef typename conditional<is_const<_Tp>::value, const char,
                                char>::type _CharType;

    struct  _ArrayInStructT { _Tp __data_[1]; };
    _ALIGNAS_TYPE(_ArrayInStructT) _CharType __elems_[sizeof(_ArrayInStructT)];

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    value_type* data() _NOEXCEPT {return nullptr;}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const value_type* data() const _NOEXCEPT {return nullptr;}

    // No explicit construct/copy/destroy for aggregate type
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    void fill(const value_type&) {
      static_assert(!is_const<_Tp>::value,
                    "cannot fill zero-sized array of type 'const T'");
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
    void swap(array&) _NOEXCEPT {
      static_assert(!is_const<_Tp>::value,
                    "cannot swap zero-sized array of type 'const T'");
    }

    // iterators:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    iterator begin() _NOEXCEPT {return iterator(data());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator begin() const _NOEXCEPT {return const_iterator(data());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    iterator end() _NOEXCEPT {return iterator(data());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator end() const _NOEXCEPT {return const_iterator(data());}

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator rbegin() const _NOEXCEPT {return const_reverse_iterator(end());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator rend() const _NOEXCEPT {return const_reverse_iterator(begin());}

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator cbegin() const _NOEXCEPT {return begin();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_iterator cend() const _NOEXCEPT {return end();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    const_reverse_iterator crend() const _NOEXCEPT {return rend();}

    // capacity:
    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT {return 0; }
    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT {return 0;}
    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {return true;}

    // element access:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference operator[](size_type) _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
    const_reference operator[](size_type) const _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference at(size_type) {
      __throw_out_of_range("array<T, 0>::at");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
    const_reference at(size_type) const {
      __throw_out_of_range("array<T, 0>::at");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference front() _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
    const_reference front() const _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference back() _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
      __libcpp_unreachable();
    }

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
    const_reference back() const _NOEXCEPT {
      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
      __libcpp_unreachable();
    }
};


#if _LIBCPP_STD_VER > 14
template<class _Tp, class... _Args,
         class = enable_if_t<__all<_IsSame<_Tp, _Args>::value...>::value>
         >
array(_Tp, _Args...)
  -> array<_Tp, 1 + sizeof...(_Args)>;
#endif

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator==(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return _VSTD::equal(__x.begin(), __x.end(), __y.begin());
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator!=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return !(__x == __y);
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator<(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return _VSTD::lexicographical_compare(__x.begin(), __x.end(),
                                          __y.begin(), __y.end());
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator>(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return __y < __x;
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator<=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return !(__y < __x);
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
operator>=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
{
    return !(__x < __y);
}

template <class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
typename enable_if
<
    _Size == 0 ||
    __is_swappable<_Tp>::value,
    void
>::type
swap(array<_Tp, _Size>& __x, array<_Tp, _Size>& __y)
                                  _NOEXCEPT_(noexcept(__x.swap(__y)))
{
    __x.swap(__y);
}

template <class _Tp, size_t _Size>
struct _LIBCPP_TEMPLATE_VIS tuple_size<array<_Tp, _Size> >
    : public integral_constant<size_t, _Size> {};

template <size_t _Ip, class _Tp, size_t _Size>
struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, array<_Tp, _Size> >
{
    static_assert(_Ip < _Size, "Index out of bounds in std::tuple_element<> (std::array)");
    typedef _Tp type;
};

template <size_t _Ip, class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp&
get(array<_Tp, _Size>& __a) _NOEXCEPT
{
    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array)");
    return __a.__elems_[_Ip];
}

template <size_t _Ip, class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
const _Tp&
get(const array<_Tp, _Size>& __a) _NOEXCEPT
{
    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array)");
    return __a.__elems_[_Ip];
}

template <size_t _Ip, class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp&&
get(array<_Tp, _Size>&& __a) _NOEXCEPT
{
    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array &&)");
    return _VSTD::move(__a.__elems_[_Ip]);
}

template <size_t _Ip, class _Tp, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
const _Tp&&
get(const array<_Tp, _Size>&& __a) _NOEXCEPT
{
    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array &&)");
    return _VSTD::move(__a.__elems_[_Ip]);
}

#if _LIBCPP_STD_VER > 17

template <typename _Tp, size_t _Size, size_t... _Index>
_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
__to_array_lvalue_impl(_Tp (&__arr)[_Size], index_sequence<_Index...>) {
  return {{__arr[_Index]...}};
}

template <typename _Tp, size_t _Size, size_t... _Index>
_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
__to_array_rvalue_impl(_Tp(&&__arr)[_Size], index_sequence<_Index...>) {
  return {{_VSTD::move(__arr[_Index])...}};
}

template <typename _Tp, size_t _Size>
_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
to_array(_Tp (&__arr)[_Size]) noexcept(is_nothrow_constructible_v<_Tp, _Tp&>) {
  static_assert(
      !is_array_v<_Tp>,
      "[array.creation]/1: to_array does not accept multidimensional arrays.");
  static_assert(
      is_constructible_v<_Tp, _Tp&>,
      "[array.creation]/1: to_array requires copy constructible elements.");
  return _VSTD::__to_array_lvalue_impl(__arr, make_index_sequence<_Size>());
}

template <typename _Tp, size_t _Size>
_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
to_array(_Tp(&&__arr)[_Size]) noexcept(is_nothrow_move_constructible_v<_Tp>) {
  static_assert(
      !is_array_v<_Tp>,
      "[array.creation]/4: to_array does not accept multidimensional arrays.");
  static_assert(
      is_move_constructible_v<_Tp>,
      "[array.creation]/4: to_array requires move constructible elements.");
  return _VSTD::__to_array_rvalue_impl(_VSTD::move(__arr),
                                       make_index_sequence<_Size>());
}

#endif // _LIBCPP_STD_VER > 17

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_ARRAY