/*
//@HEADER
// ************************************************************************
//
//                        Kokkos v. 2.0
//              Copyright (2019) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact Christian R. Trott (crtrott@sandia.gov)
//
// ************************************************************************
//@HEADER
*/

#ifndef _LIBCUDACXX___MDSPAN_MACROS_HPP
#define _LIBCUDACXX___MDSPAN_MACROS_HPP

#include <cuda/std/detail/__config>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cuda/std/__mdspan/config.h>
#include <cuda/std/__type_traits/enable_if.h>
#include <cuda/std/__type_traits/is_void.h>
#include <cuda/std/__type_traits/remove_reference.h>
#include <cuda/std/__utility/declval.h>

#if _CCCL_STD_VER > 2011

#  ifndef __MDSPAN_FORCE_INLINE_FUNCTION
#    ifdef __MDSPAN_COMPILER_MSVC // Microsoft compilers
#      define __MDSPAN_FORCE_INLINE_FUNCTION __forceinline _CCCL_HOST_DEVICE
#    else
#      define __MDSPAN_FORCE_INLINE_FUNCTION __attribute__((always_inline)) _CCCL_HOST_DEVICE
#    endif
#  endif

#  ifndef __MDSPAN_INLINE_FUNCTION
#    define __MDSPAN_INLINE_FUNCTION inline _CCCL_HOST_DEVICE
#  endif

// In CUDA defaulted functions do not need host device markup
#  ifndef __MDSPAN_INLINE_FUNCTION_DEFAULTED
#    define __MDSPAN_INLINE_FUNCTION_DEFAULTED
#  endif

//==============================================================================
// <editor-fold desc="Preprocessor helpers"> {{{1

#  define __MDSPAN_PP_COUNT(...) \
    __MDSPAN_PP_INTERNAL_EXPAND_ARGS_PRIVATE(__MDSPAN_PP_INTERNAL_ARGS_AUGMENTER(__VA_ARGS__))

#  define __MDSPAN_PP_INTERNAL_ARGS_AUGMENTER(...) unused, __VA_ARGS__
#  define __MDSPAN_PP_INTERNAL_EXPAND(x)           x
#  define __MDSPAN_PP_INTERNAL_EXPAND_ARGS_PRIVATE(...)             \
    __MDSPAN_PP_INTERNAL_EXPAND(__MDSPAN_PP_INTERNAL_COUNT_PRIVATE( \
      __VA_ARGS__,                                                  \
      69,                                                           \
      68,                                                           \
      67,                                                           \
      66,                                                           \
      65,                                                           \
      64,                                                           \
      63,                                                           \
      62,                                                           \
      61,                                                           \
      60,                                                           \
      59,                                                           \
      58,                                                           \
      57,                                                           \
      56,                                                           \
      55,                                                           \
      54,                                                           \
      53,                                                           \
      52,                                                           \
      51,                                                           \
      50,                                                           \
      49,                                                           \
      48,                                                           \
      47,                                                           \
      46,                                                           \
      45,                                                           \
      44,                                                           \
      43,                                                           \
      42,                                                           \
      41,                                                           \
      40,                                                           \
      39,                                                           \
      38,                                                           \
      37,                                                           \
      36,                                                           \
      35,                                                           \
      34,                                                           \
      33,                                                           \
      32,                                                           \
      31,                                                           \
      30,                                                           \
      29,                                                           \
      28,                                                           \
      27,                                                           \
      26,                                                           \
      25,                                                           \
      24,                                                           \
      23,                                                           \
      22,                                                           \
      21,                                                           \
      20,                                                           \
      19,                                                           \
      18,                                                           \
      17,                                                           \
      16,                                                           \
      15,                                                           \
      14,                                                           \
      13,                                                           \
      12,                                                           \
      11,                                                           \
      10,                                                           \
      9,                                                            \
      8,                                                            \
      7,                                                            \
      6,                                                            \
      5,                                                            \
      4,                                                            \
      3,                                                            \
      2,                                                            \
      1,                                                            \
      0))
#  define __MDSPAN_PP_INTERNAL_COUNT_PRIVATE( \
    _1_,                                      \
    _2_,                                      \
    _3_,                                      \
    _4_,                                      \
    _5_,                                      \
    _6_,                                      \
    _7_,                                      \
    _8_,                                      \
    _9_,                                      \
    _10,                                      \
    _11,                                      \
    _12,                                      \
    _13,                                      \
    _14,                                      \
    _15,                                      \
    _16,                                      \
    _17,                                      \
    _18,                                      \
    _19,                                      \
    _20,                                      \
    _21,                                      \
    _22,                                      \
    _23,                                      \
    _24,                                      \
    _25,                                      \
    _26,                                      \
    _27,                                      \
    _28,                                      \
    _29,                                      \
    _30,                                      \
    _31,                                      \
    _32,                                      \
    _33,                                      \
    _34,                                      \
    _35,                                      \
    _36,                                      \
    _37,                                      \
    _38,                                      \
    _39,                                      \
    _40,                                      \
    _41,                                      \
    _42,                                      \
    _43,                                      \
    _44,                                      \
    _45,                                      \
    _46,                                      \
    _47,                                      \
    _48,                                      \
    _49,                                      \
    _50,                                      \
    _51,                                      \
    _52,                                      \
    _53,                                      \
    _54,                                      \
    _55,                                      \
    _56,                                      \
    _57,                                      \
    _58,                                      \
    _59,                                      \
    _60,                                      \
    _61,                                      \
    _62,                                      \
    _63,                                      \
    _64,                                      \
    _65,                                      \
    _66,                                      \
    _67,                                      \
    _68,                                      \
    _69,                                      \
    _70,                                      \
    count,                                    \
    ...)                                      \
    count /**/

#  define __MDSPAN_PP_STRINGIFY_IMPL(x) #x
#  define __MDSPAN_PP_STRINGIFY(x)      __MDSPAN_PP_STRINGIFY_IMPL(x)

#  define __MDSPAN_PP_CAT_IMPL(x, y) x##y
#  define __MDSPAN_PP_CAT(x, y)      __MDSPAN_PP_CAT_IMPL(x, y)

#  define __MDSPAN_PP_EVAL(X, ...) X(__VA_ARGS__)

#  define __MDSPAN_PP_REMOVE_PARENS_IMPL(...) __VA_ARGS__
#  define __MDSPAN_PP_REMOVE_PARENS(...)      __MDSPAN_PP_REMOVE_PARENS_IMPL __VA_ARGS__

// </editor-fold> end Preprocessor helpers }}}1
//==============================================================================

//==============================================================================
// <editor-fold desc="Concept emulation"> {{{1

// These compatibility macros don't help with partial ordering, but they should do the trick
// for what we need to do with concepts in mdspan
#  ifdef __MDSPAN_USE_CONCEPTS
#    define __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) \
      >                                        \
          requires REQ
#    define __MDSPAN_FUNCTION_REQUIRES(PAREN_PREQUALS, FNAME, PAREN_PARAMS, QUALS, REQ) \
      __MDSPAN_PP_REMOVE_PARENS(PAREN_PREQUALS)                                         \
      FNAME PAREN_PARAMS QUALS                                                          \
        requires REQ /**/
#  else
#    define __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) , typename _CUDA_VSTD::enable_if<(REQ), int>::type = 0 >
#    define __MDSPAN_FUNCTION_REQUIRES(PAREN_PREQUALS, FNAME, PAREN_PARAMS, QUALS, REQ)                             \
      __MDSPAN_TEMPLATE_REQUIRES(                                                                                   \
        class __function_requires_ignored = void, (_CUDA_VSTD::is_void<__function_requires_ignored>::value && REQ)) \
      __MDSPAN_PP_REMOVE_PARENS(PAREN_PREQUALS) FNAME PAREN_PARAMS QUALS /**/
#  endif

#  if defined(__MDSPAN_COMPILER_MSVC)
#    define __MDSPAN_TEMPLATE_REQUIRES(...)                                                                        \
      __MDSPAN_PP_CAT(__MDSPAN_PP_CAT(__MDSPAN_TEMPLATE_REQUIRES_, __MDSPAN_PP_COUNT(__VA_ARGS__))(__VA_ARGS__), ) \
      /**/
#  else
#    define __MDSPAN_TEMPLATE_REQUIRES(...)                                                                       \
      __MDSPAN_PP_EVAL(__MDSPAN_PP_CAT(__MDSPAN_TEMPLATE_REQUIRES_, __MDSPAN_PP_COUNT(__VA_ARGS__)), __VA_ARGS__) \
      /**/
#  endif

#  define __MDSPAN_TEMPLATE_REQUIRES_2(TP1, REQ)      template <TP1 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_3(TP1, TP2, REQ) template <TP1, TP2 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_4(TP1, TP2, TP3, REQ) \
    template <TP1, TP2, TP3 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_5(TP1, TP2, TP3, TP4, REQ) \
    template <TP1, TP2, TP3, TP4 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_6(TP1, TP2, TP3, TP4, TP5, REQ) \
    template <TP1, TP2, TP3, TP4, TP5 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_7(TP1, TP2, TP3, TP4, TP5, TP6, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_8(TP1, TP2, TP3, TP4, TP5, TP6, TP7, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_9(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_10(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_11(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_12(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_13(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_14(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_15(TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, REQ) \
    template <TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_16(                                                  \
    TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP15, REQ) \
    template <TP1,                                                                        \
              TP2,                                                                        \
              TP3,                                                                        \
              TP4,                                                                        \
              TP5,                                                                        \
              TP6,                                                                        \
              TP7,                                                                        \
              TP8,                                                                        \
              TP9,                                                                        \
              TP10,                                                                       \
              TP11,                                                                       \
              TP12,                                                                       \
              TP13,                                                                       \
              TP14,                                                                       \
              TP15 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_17(                                                        \
    TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP15, TP16, REQ) \
    template <TP1,                                                                              \
              TP2,                                                                              \
              TP3,                                                                              \
              TP4,                                                                              \
              TP5,                                                                              \
              TP6,                                                                              \
              TP7,                                                                              \
              TP8,                                                                              \
              TP9,                                                                              \
              TP10,                                                                             \
              TP11,                                                                             \
              TP12,                                                                             \
              TP13,                                                                             \
              TP14,                                                                             \
              TP15,                                                                             \
              TP16 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_18(                                                              \
    TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP15, TP16, TP17, REQ) \
    template <TP1,                                                                                    \
              TP2,                                                                                    \
              TP3,                                                                                    \
              TP4,                                                                                    \
              TP5,                                                                                    \
              TP6,                                                                                    \
              TP7,                                                                                    \
              TP8,                                                                                    \
              TP9,                                                                                    \
              TP10,                                                                                   \
              TP11,                                                                                   \
              TP12,                                                                                   \
              TP13,                                                                                   \
              TP14,                                                                                   \
              TP15,                                                                                   \
              TP16,                                                                                   \
              TP17 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_19(                                                                    \
    TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP15, TP16, TP17, TP18, REQ) \
    template <TP1,                                                                                          \
              TP2,                                                                                          \
              TP3,                                                                                          \
              TP4,                                                                                          \
              TP5,                                                                                          \
              TP6,                                                                                          \
              TP7,                                                                                          \
              TP8,                                                                                          \
              TP9,                                                                                          \
              TP10,                                                                                         \
              TP11,                                                                                         \
              TP12,                                                                                         \
              TP13,                                                                                         \
              TP14,                                                                                         \
              TP15,                                                                                         \
              TP16,                                                                                         \
              TP17,                                                                                         \
              TP18 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/
#  define __MDSPAN_TEMPLATE_REQUIRES_20(                                                                          \
    TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP15, TP16, TP17, TP18, TP19, REQ) \
    template <TP1,                                                                                                \
              TP2,                                                                                                \
              TP3,                                                                                                \
              TP4,                                                                                                \
              TP5,                                                                                                \
              TP6,                                                                                                \
              TP7,                                                                                                \
              TP8,                                                                                                \
              TP9,                                                                                                \
              TP10,                                                                                               \
              TP11,                                                                                               \
              TP12,                                                                                               \
              TP13,                                                                                               \
              TP14,                                                                                               \
              TP15,                                                                                               \
              TP16,                                                                                               \
              TP17,                                                                                               \
              TP18,                                                                                               \
              TP19 __MDSPAN_CLOSE_ANGLE_REQUIRES(REQ) /**/

#  define __MDSPAN_INSTANTIATE_ONLY_IF_USED                                                           \
    __MDSPAN_TEMPLATE_REQUIRES(class __instantiate_only_if_used_tparam = void,                        \
                               (_CCCL_TRAIT(_CUDA_VSTD::is_void, __instantiate_only_if_used_tparam))) \
    /**/

// </editor-fold> end Concept emulation }}}1
//==============================================================================

//==============================================================================
// <editor-fold desc="Return type deduction"> {{{1

#  if __MDSPAN_USE_RETURN_TYPE_DEDUCTION
#    define __MDSPAN_DEDUCE_RETURN_TYPE_SINGLE_LINE(SIGNATURE, BODY) \
      auto __MDSPAN_PP_REMOVE_PARENS(SIGNATURE)                      \
      {                                                              \
        return __MDSPAN_PP_REMOVE_PARENS(BODY);                      \
      }
#    define __MDSPAN_DEDUCE_DECLTYPE_AUTO_RETURN_TYPE_SINGLE_LINE(SIGNATURE, BODY) \
      decltype(auto) __MDSPAN_PP_REMOVE_PARENS(SIGNATURE)                          \
      {                                                                            \
        return __MDSPAN_PP_REMOVE_PARENS(BODY);                                    \
      }
#  else
#    define __MDSPAN_DEDUCE_RETURN_TYPE_SINGLE_LINE(SIGNATURE, BODY)               \
      auto __MDSPAN_PP_REMOVE_PARENS(SIGNATURE)                                    \
        -> _CUDA_VSTD::remove_cv_t<_CUDA_VSTD::remove_reference_t<decltype(BODY)>> \
      {                                                                            \
        return __MDSPAN_PP_REMOVE_PARENS(BODY);                                    \
      }
#    define __MDSPAN_DEDUCE_DECLTYPE_AUTO_RETURN_TYPE_SINGLE_LINE(SIGNATURE, BODY) \
      auto __MDSPAN_PP_REMOVE_PARENS(SIGNATURE) -> decltype(BODY)                  \
      {                                                                            \
        return __MDSPAN_PP_REMOVE_PARENS(BODY);                                    \
      }

#  endif

// </editor-fold> end Return type deduction }}}1
//==============================================================================

//==============================================================================
// <editor-fold desc="fold expressions"> {{{1

struct __mdspan_enable_fold_comma
{};

#  ifdef __MDSPAN_USE_FOLD_EXPRESSIONS
#    define __MDSPAN_FOLD_AND(...)                  ((__VA_ARGS__) && ...)
#    define __MDSPAN_FOLD_AND_TEMPLATE(...)         ((__VA_ARGS__) && ...)
#    define __MDSPAN_FOLD_OR(...)                   ((__VA_ARGS__) || ...)
#    define __MDSPAN_FOLD_ASSIGN_LEFT(__INIT, ...)  (__INIT = ... = (__VA_ARGS__))
#    define __MDSPAN_FOLD_ASSIGN_RIGHT(__PACK, ...) (__PACK = ... = (__VA_ARGS__))
#    define __MDSPAN_FOLD_TIMES_RIGHT(__PACK, ...)  (__PACK * ... * (__VA_ARGS__))
#    define __MDSPAN_FOLD_PLUS_RIGHT(__PACK, ...)   (__PACK + ... + (__VA_ARGS__))
#    define __MDSPAN_FOLD_COMMA(...)                ((__VA_ARGS__), ...)
#  else

_LIBCUDACXX_BEGIN_NAMESPACE_STD

namespace __fold_compatibility_impl
{

// We could probably be more clever here, but at the (small) risk of losing some compiler understanding.  For the
// few operations we need, it's not worth generalizing over the operation

#    if __MDSPAN_USE_RETURN_TYPE_DEDUCTION

__MDSPAN_FORCE_INLINE_FUNCTION
constexpr decltype(auto) __fold_right_and_impl()
{
  return true;
}

template <class _Arg, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr decltype(auto) __fold_right_and_impl(_Arg&& __arg, _Args&&... __args)
{
  return ((_Arg&&) __arg) && __fold_compatibility_impl::__fold_right_and_impl((_Args&&) __args...);
}

__MDSPAN_FORCE_INLINE_FUNCTION
constexpr decltype(auto) __fold_right_or_impl()
{
  return false;
}

template <class _Arg, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_or_impl(_Arg&& __arg, _Args&&... __args)
{
  return ((_Arg&&) __arg) || __fold_compatibility_impl::__fold_right_or_impl((_Args&&) __args...);
}

template <class _Arg1>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_left_assign_impl(_Arg1&& __arg1)
{
  return (_Arg1&&) __arg1;
}

template <class _Arg1, class _Arg2, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_left_assign_impl(_Arg1&& __arg1, _Arg2&& __arg2, _Args&&... __args)
{
  return __fold_compatibility_impl::__fold_left_assign_impl(
    (((_Arg1&&) __arg1) = ((_Arg2&&) __arg2)), (_Args&&) __args...);
}

template <class _Arg1>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_assign_impl(_Arg1&& __arg1)
{
  return (_Arg1&&) __arg1;
}

template <class _Arg1, class _Arg2, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_assign_impl(_Arg1&& __arg1, _Arg2&& __arg2, _Args&&... __args)
{
  return ((_Arg1&&) __arg1) =
           __fold_compatibility_impl::__fold_right_assign_impl((_Arg2&&) __arg2, (_Args&&) __args...);
}

template <class _Arg1>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_plus_impl(_Arg1&& __arg1)
{
  return (_Arg1&&) __arg1;
}

template <class _Arg1, class _Arg2, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_plus_impl(_Arg1&& __arg1, _Arg2&& __arg2, _Args&&... __args)
{
  return ((_Arg1&&) __arg1) + __fold_compatibility_impl::__fold_right_plus_impl((_Arg2&&) __arg2, (_Args&&) __args...);
}

template <class _Arg1>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_times_impl(_Arg1&& __arg1)
{
  return (_Arg1&&) __arg1;
}

template <class _Arg1, class _Arg2, class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr auto __fold_right_times_impl(_Arg1&& __arg1, _Arg2&& __arg2, _Args&&... __args)
{
  return ((_Arg1&&) __arg1) * __fold_compatibility_impl::__fold_right_times_impl((_Arg2&&) __arg2, (_Args&&) __args...);
}

#    else

//------------------------------------------------------------------------------
// <editor-fold desc="right and"> {{{2

template <class... _Args>
struct __fold_right_and_impl_;
template <>
struct __fold_right_and_impl_<>
{
  using __rv = bool;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl() noexcept
  {
    return true;
  }
};
template <class _Arg, class... _Args>
struct __fold_right_and_impl_<_Arg, _Args...>
{
  using __next_t = __fold_right_and_impl_<_Args...>;
  using __rv     = decltype(_CUDA_VSTD::declval<_Arg>() && _CUDA_VSTD::declval<typename __next_t::__rv>());
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg, _Args&&... __args) noexcept
  {
    return ((_Arg&&) __arg) && __next_t::__impl((_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_right_and_impl_<_Args...>::__rv
__fold_right_and_impl(_Args&&... __args)
{
  return __fold_right_and_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end right and }}}2
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// <editor-fold desc="right or"> {{{2

template <class... _Args>
struct __fold_right_or_impl_;
template <>
struct __fold_right_or_impl_<>
{
  using __rv = bool;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl() noexcept
  {
    return false;
  }
};
template <class _Arg, class... _Args>
struct __fold_right_or_impl_<_Arg, _Args...>
{
  using __next_t = __fold_right_or_impl_<_Args...>;
  using __rv     = decltype(_CUDA_VSTD::declval<_Arg>() || _CUDA_VSTD::declval<typename __next_t::__rv>());
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg, _Args&&... __args) noexcept
  {
    return ((_Arg&&) __arg) || __next_t::__impl((_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_right_or_impl_<_Args...>::__rv
__fold_right_or_impl(_Args&&... __args)
{
  return __fold_right_or_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end right or }}}2
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// <editor-fold desc="right plus"> {{{2

template <class... _Args>
struct __fold_right_plus_impl_;
template <class _Arg>
struct __fold_right_plus_impl_<_Arg>
{
  using __rv = _Arg&&;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg) noexcept
  {
    return (_Arg&&) __arg;
  }
};
template <class _Arg1, class _Arg2, class... _Args>
struct __fold_right_plus_impl_<_Arg1, _Arg2, _Args...>
{
  using __next_t = __fold_right_plus_impl_<_Arg2, _Args...>;
  using __rv     = decltype(_CUDA_VSTD::declval<_Arg1>() + _CUDA_VSTD::declval<typename __next_t::__rv>());
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg1&& __arg, _Arg2&& __arg2, _Args&&... __args) noexcept
  {
    return ((_Arg1&&) __arg) + __next_t::__impl((_Arg2&&) __arg2, (_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_right_plus_impl_<_Args...>::__rv
__fold_right_plus_impl(_Args&&... __args)
{
  return __fold_right_plus_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end right plus }}}2
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// <editor-fold desc="right times"> {{{2

template <class... _Args>
struct __fold_right_times_impl_;
template <class _Arg>
struct __fold_right_times_impl_<_Arg>
{
  using __rv = _Arg&&;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg) noexcept
  {
    return (_Arg&&) __arg;
  }
};
template <class _Arg1, class _Arg2, class... _Args>
struct __fold_right_times_impl_<_Arg1, _Arg2, _Args...>
{
  using __next_t = __fold_right_times_impl_<_Arg2, _Args...>;
  using __rv     = decltype(_CUDA_VSTD::declval<_Arg1>() * _CUDA_VSTD::declval<typename __next_t::__rv>());
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg1&& __arg, _Arg2&& __arg2, _Args&&... __args) noexcept
  {
    return ((_Arg1&&) __arg) * __next_t::__impl((_Arg2&&) __arg2, (_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_right_times_impl_<_Args...>::__rv
__fold_right_times_impl(_Args&&... __args)
{
  return __fold_right_times_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end right times }}}2
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// <editor-fold desc="right assign"> {{{2

template <class... _Args>
struct __fold_right_assign_impl_;
template <class _Arg>
struct __fold_right_assign_impl_<_Arg>
{
  using __rv = _Arg&&;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg) noexcept
  {
    return (_Arg&&) __arg;
  }
};
template <class _Arg1, class _Arg2, class... _Args>
struct __fold_right_assign_impl_<_Arg1, _Arg2, _Args...>
{
  using __next_t = __fold_right_assign_impl_<_Arg2, _Args...>;
  using __rv     = decltype(_CUDA_VSTD::declval<_Arg1>() = _CUDA_VSTD::declval<typename __next_t::__rv>());
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg1&& __arg, _Arg2&& __arg2, _Args&&... __args) noexcept
  {
    return ((_Arg1&&) __arg) = __next_t::__impl((_Arg2&&) __arg2, (_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_right_assign_impl_<_Args...>::__rv
__fold_right_assign_impl(_Args&&... __args)
{
  return __fold_right_assign_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end right assign }}}2
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// <editor-fold desc="left assign"> {{{2

template <class... _Args>
struct __fold_left_assign_impl_;
template <class _Arg>
struct __fold_left_assign_impl_<_Arg>
{
  using __rv = _Arg&&;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg&& __arg) noexcept
  {
    return (_Arg&&) __arg;
  }
};
template <class _Arg1, class _Arg2, class... _Args>
struct __fold_left_assign_impl_<_Arg1, _Arg2, _Args...>
{
  using __assign_result_t = decltype(_CUDA_VSTD::declval<_Arg1>() = _CUDA_VSTD::declval<_Arg2>());
  using __next_t          = __fold_left_assign_impl_<__assign_result_t, _Args...>;
  using __rv              = typename __next_t::__rv;
  __MDSPAN_FORCE_INLINE_FUNCTION
  static constexpr __rv __impl(_Arg1&& __arg, _Arg2&& __arg2, _Args&&... __args) noexcept
  {
    return __next_t::__impl(((_Arg1&&) __arg) = (_Arg2&&) __arg2, (_Args&&) __args...);
  }
};

template <class... _Args>
__MDSPAN_FORCE_INLINE_FUNCTION constexpr typename __fold_left_assign_impl_<_Args...>::__rv
__fold_left_assign_impl(_Args&&... __args)
{
  return __fold_left_assign_impl_<_Args...>::__impl((_Args&&) __args...);
}

// </editor-fold> end left assign }}}2
//------------------------------------------------------------------------------

#    endif

template <class... _Args>
_CCCL_HOST_DEVICE constexpr __mdspan_enable_fold_comma __fold_comma_impl(_Args&&...) noexcept
{
  return {};
}

template <bool... _Bs>
struct __bools;

} // namespace __fold_compatibility_impl

_LIBCUDACXX_END_NAMESPACE_STD

#    define __MDSPAN_FOLD_AND(...) _CUDA_VSTD::__fold_compatibility_impl::__fold_right_and_impl((__VA_ARGS__)...)
#    define __MDSPAN_FOLD_OR(...)  _CUDA_VSTD::__fold_compatibility_impl::__fold_right_or_impl((__VA_ARGS__)...)
#    define __MDSPAN_FOLD_ASSIGN_LEFT(__INIT, ...) \
      _CUDA_VSTD::__fold_compatibility_impl::__fold_left_assign_impl(__INIT, (__VA_ARGS__)...)
#    define __MDSPAN_FOLD_ASSIGN_RIGHT(__PACK, ...) \
      _CUDA_VSTD::__fold_compatibility_impl::__fold_right_assign_impl((__PACK)..., __VA_ARGS__)
#    define __MDSPAN_FOLD_TIMES_RIGHT(__PACK, ...) \
      _CUDA_VSTD::__fold_compatibility_impl::__fold_right_times_impl((__PACK)..., __VA_ARGS__)
#    define __MDSPAN_FOLD_PLUS_RIGHT(__PACK, ...) \
      _CUDA_VSTD::__fold_compatibility_impl::__fold_right_plus_impl((__PACK)..., __VA_ARGS__)
#    define __MDSPAN_FOLD_COMMA(...) _CUDA_VSTD::__fold_compatibility_impl::__fold_comma_impl((__VA_ARGS__)...)

#    define __MDSPAN_FOLD_AND_TEMPLATE(...)                                   \
      _CCCL_TRAIT(_CUDA_VSTD::is_same,                                        \
                  __fold_compatibility_impl::__bools<(__VA_ARGS__)..., true>, \
                  __fold_compatibility_impl::__bools<true, (__VA_ARGS__)...>)

#  endif

// </editor-fold> end Variable template compatibility }}}1
//==============================================================================

//==============================================================================
// <editor-fold desc="Pre-C++14 constexpr"> {{{1

#  if __MDSPAN_USE_CONSTEXPR_14
// Workaround for a bug (I think?) in EDG frontends
#    ifdef __EDG__
#      define __MDSPAN_CONSTEXPR_14_DEFAULTED
#    else
#      define __MDSPAN_CONSTEXPR_14_DEFAULTED constexpr
#    endif
#  else
#    define __MDSPAN_CONSTEXPR_14_DEFAULTED
#  endif

// </editor-fold> end Pre-C++14 constexpr }}}1
//==============================================================================

#endif // _CCCL_STD_VER > 2011

#ifndef _LIBCUDACXX_NO_EXCEPTIONS
#  define _LIBCUDACXX_THROW_RUNTIME_ERROR(_COND, _MESSAGE) \
    if (!(_COND))                                          \
    __throw_runtime_error(_MESSAGE)
#else
#  define _LIBCUDACXX_THROW_RUNTIME_ERROR(_COND, _MESSAGE) _LIBCUDACXX_ASSERT(_COND, _MESSAGE)
#endif

#endif // _LIBCUDACXX___MDSPAN_MACROS_HPP