[libc++][NFC] Rename iterator category checks to make it obvious that they check //only// the iterator category

[philnik]

Summary

We plan to add concepts for checking that iterators actually provide what they claim to. This is to avoid people thinking that these type traits actually check the iterator requirements in more detail.

[Mordante]

Can you add information in the commit message why this change is needed?

[ldionne]

LGTM w/ comment.

libcxx/include/__iterator/iterator_traits.h

476

Maybe __libcpp_is_contiguous_iterator instead? It doesn't imply anything about C++17 or whether we check for a specific category/concept.

libcxx/include/__algorithm/copy.h

operator()(_InIter __first, _InIter __last, _OutIter __result) const {
     }
     __result =
         std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
     return std::make_pair(__last, std::move(__result));
   }
 
   template <class _InIter,
             class _OutIter,
-            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
   operator()(_InIter __first, _InIter __last, _OutIter __result) {
     using _Traits = __segmented_iterator_traits<_OutIter>;
     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
 
     if (__first == __last)

libcxx/include/__algorithm/copy_backward.h

operator()(_InIter __first, _InIter __last, _OutIter __result) const {
     }
     __result = std::__copy_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
                    .second;
     return std::make_pair(__last, std::move(__result));
   }
 
   template <class _InIter,
             class _OutIter,
-            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
   operator()(_InIter __first, _InIter __last, _OutIter __result) {
     using _Traits           = __segmented_iterator_traits<_OutIter>;
     auto __orig_last        = __last;
     auto __segment_iterator = _Traits::__segment(__result);
 

libcxx/include/__algorithm/copy_n.h

 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template<class _InputIterator, class _Size, class _OutputIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename enable_if
 <
-    __is_cpp17_input_iterator<_InputIterator>::value &&
-   !__is_cpp17_random_access_iterator<_InputIterator>::value,
+    __has_input_iterator_category<_InputIterator>::value &&
+   !__has_random_access_iterator_category<_InputIterator>::value,
     _OutputIterator
 >::type
 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
 {
     typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
     _IntegralSize __n = __orig_n;
     if (__n > 0)
     {
         *__result = *__first;
         ++__result;
         for (--__n; __n > 0; --__n)
         {
             ++__first;
             *__result = *__first;
             ++__result;
         }
     }
     return __result;
 }
 
 template<class _InputIterator, class _Size, class _OutputIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename enable_if
 <
-    __is_cpp17_random_access_iterator<_InputIterator>::value,
+    __has_random_access_iterator_category<_InputIterator>::value,
     _OutputIterator
 >::type
 copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
 {
     typedef typename iterator_traits<_InputIterator>::difference_type difference_type;
     typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
     _IntegralSize __n = __orig_n;
     return _VSTD::copy(__first, __first + difference_type(__n), __result);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_COPY_N_H

libcxx/include/__algorithm/lexicographical_compare_three_way.h

 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto lexicographical_compare_three_way(
     _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Cmp __comp)
     -> decltype(__comp(*__first1, *__first2)) {
   static_assert(__comparison_category<decltype(__comp(*__first1, *__first2))>,
                 "The comparator passed to lexicographical_compare_three_way must return a comparison category type.");
   static_assert(std::is_copy_constructible_v<_InputIterator1>, "Iterators must be copy constructible.");
   static_assert(std::is_copy_constructible_v<_InputIterator2>, "Iterators must be copy constructible.");
   __three_way_comp_ref_type<_Cmp> __wrapped_comp_ref(__comp);
-  if constexpr (__is_cpp17_random_access_iterator<_InputIterator1>::value &&
-                __is_cpp17_random_access_iterator<_InputIterator2>::value) {
+  if constexpr (__has_random_access_iterator_category<_InputIterator1>::value &&
+                __has_random_access_iterator_category<_InputIterator2>::value) {
     return std::__lexicographical_compare_three_way_fast_path(
         std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __wrapped_comp_ref);
   } else {
     // Unoptimized implementation which compares the iterators against the end in every loop iteration
     return std::__lexicographical_compare_three_way_slow_path(
         std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __wrapped_comp_ref);
   }
 }

libcxx/include/__algorithm/max_element.h

 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Compare, class _ForwardIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
 __max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
 {
-    static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+    static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
         "std::max_element requires a ForwardIterator");
     if (__first != __last)
     {
         _ForwardIterator __i = __first;
         while (++__i != __last)
             if (__comp(*__first, *__i))
                 __first = __i;
     }

libcxx/include/__algorithm/min_element.h

_Iter __min_element(_Iter __first, _Sent __last, _Comp __comp) {
   auto __proj = __identity();
   return std::__min_element<_Comp>(std::move(__first), std::move(__last), __comp, __proj);
 }
 
 template <class _ForwardIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
 min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
 {
-  static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+  static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
       "std::min_element requires a ForwardIterator");
   static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
               "The comparator has to be callable");
 
   return std::__min_element<__comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp);
 }
 
 template <class _ForwardIterator>

libcxx/include/__algorithm/minmax_element.h

pair<_Iter, _Iter> __minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {
 
   return __result;
 }
 
 template <class _ForwardIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_ForwardIterator, _ForwardIterator>
 minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {
-  static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+  static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
                 "std::minmax_element requires a ForwardIterator");
   static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
                 "The comparator has to be callable");
   auto __proj = __identity();
   return std::__minmax_element_impl(__first, __last, __comp, __proj);
 }
 
 template <class _ForwardIterator>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_ForwardIterator, _ForwardIterator> minmax_element(_ForwardIterator __first, _ForwardIterator __last) {
     return std::minmax_element(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H

libcxx/include/__algorithm/move.h

operator()(_InIter __first, _InIter __last, _OutIter __result) const {
     }
     __result =
         std::__move<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
     return std::make_pair(__last, std::move(__result));
   }
 
   template <class _InIter,
             class _OutIter,
-            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
   operator()(_InIter __first, _InIter __last, _OutIter __result) {
     using _Traits = __segmented_iterator_traits<_OutIter>;
     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
 
     if (__first == __last)

libcxx/include/__algorithm/move_backward.h

operator()(_InIter __first, _InIter __last, _OutIter __result) const {
     }
     __result = std::__move_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
                    .second;
     return std::make_pair(__last, std::move(__result));
   }
 
   template <class _InIter,
             class _OutIter,
-            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
                               !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
   operator()(_InIter __first, _InIter __last, _OutIter __result) {
     using _Traits = __segmented_iterator_traits<_OutIter>;
     using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
 
     // When the range contains no elements, __result might not be a valid iterator

libcxx/include/__algorithm/pstl_backends/cpu_backends/any_of.h

_LIBCPP_HIDE_FROM_ABI bool __simd_or(_Index __first, _DifferenceType __n, _Pred __pred) noexcept {
   }
   return false;
 }
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
 _LIBCPP_HIDE_FROM_ABI bool
 __pstl_any_of(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
     return std::__terminate_on_exception([&] {
       return std::__parallel_or(
           __first, __last, [&__pred](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
             return std::__pstl_any_of<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{}, __brick_first, __brick_last, __pred);
           });
     });
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
     return std::__simd_or(__first, __last - __first, __pred);
   } else {
     return std::any_of(__first, __last, __pred);
   }
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_ANY_OF_H

libcxx/include/__algorithm/pstl_backends/cpu_backends/fill.h

for (_DifferenceType __i = 0; __i < __n; ++__i)
     __first[__i] = __value;
   return __first + __n;
 }
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
 _LIBCPP_HIDE_FROM_ABI void
 __pstl_fill(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
     std::__terminate_on_exception([&] {
       __par_backend::__parallel_for(
           __first, __last, [&__value](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
             std::__pstl_fill<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{}, __brick_first, __brick_last, __value);
           });
     });
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
     std::__simd_fill_n(__first, __last - __first, __value);
   } else {
     std::fill(__first, __last, __value);
   }
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FILL_H

libcxx/include/__algorithm/pstl_backends/cpu_backends/find_if.h

__simd_first(_Index __first, _DifferenceType __begin, _DifferenceType __end, _Compare __comp) noexcept {
   }
   return __first + __end;
 }
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
 _LIBCPP_HIDE_FROM_ABI _ForwardIterator
 __pstl_find_if(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
     return std::__terminate_on_exception([&] {
       return std::__parallel_find(
           __first,
           __last,
           [&__pred](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
             return std::__pstl_find_if<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{}, __brick_first, __brick_last, __pred);
           },
           less<>{},
           true);
     });
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
     using __diff_t = __iter_diff_t<_ForwardIterator>;
     return std::__simd_first(__first, __diff_t(0), __last - __first, [&__pred](_ForwardIterator __iter, __diff_t __i) {
       return __pred(__iter[__i]);
     });
   } else {
     return std::find_if(__first, __last, __pred);
   }
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FIND_IF_H

libcxx/include/__algorithm/pstl_backends/cpu_backends/for_each.h

_LIBCPP_HIDE_FROM_ABI _Iterator __simd_walk_1(_Iterator __first, _DifferenceType __n, _Function __f) noexcept {
 
   return __first + __n;
 }
 
 template <class _ExecutionPolicy, class _ForwardIterator, class _Functor>
 _LIBCPP_HIDE_FROM_ABI void
 __pstl_for_each(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Functor __func) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
     std::__terminate_on_exception([&] {
       std::__par_backend::__parallel_for(
           __first, __last, [__func](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
             std::__pstl_for_each<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{}, __brick_first, __brick_last, __func);
           });
     });
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
     std::__simd_walk_1(__first, __last - __first, __func);
   } else {
     std::for_each(__first, __last, __func);
   }
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKNEDS_FOR_EACH_H

libcxx/include/__algorithm/pstl_backends/cpu_backends/transform.h

 template <class _ExecutionPolicy, class _ForwardIterator, class _ForwardOutIterator, class _UnaryOperation>
 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator __pstl_transform(
     __cpu_backend_tag,
     _ForwardIterator __first,
     _ForwardIterator __last,
     _ForwardOutIterator __result,
     _UnaryOperation __op) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator>::value &&
-                __is_cpp17_random_access_iterator<_ForwardOutIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator>::value &&
+                __has_random_access_iterator_category<_ForwardOutIterator>::value) {
     std::__terminate_on_exception([&] {
       std::__par_backend::__parallel_for(
           __first, __last, [__op, __first, __result](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
             return std::__pstl_transform<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{}, __brick_first, __brick_last, __result + (__brick_first - __first), __op);
           });
     });
     return __result + (__last - __first);
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator>::value &&
-                       __is_cpp17_random_access_iterator<_ForwardOutIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator>::value &&
+                       __has_random_access_iterator_category<_ForwardOutIterator>::value) {
     return std::__simd_walk_2(
         __first,
         __last - __first,
         __result,
         [&](__iter_reference<_ForwardIterator> __in_value, __iter_reference<_ForwardOutIterator> __out_value) {
           __out_value = __op(__in_value);
         });
   } else {

 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator __pstl_transform(
     __cpu_backend_tag,
     _ForwardIterator1 __first1,
     _ForwardIterator1 __last1,
     _ForwardIterator2 __first2,
     _ForwardOutIterator __result,
     _BinaryOperation __op) {
   if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
-                __is_cpp17_random_access_iterator<_ForwardIterator1>::value &&
-                __is_cpp17_random_access_iterator<_ForwardIterator2>::value &&
-                __is_cpp17_random_access_iterator<_ForwardOutIterator>::value) {
+                __has_random_access_iterator_category<_ForwardIterator1>::value &&
+                __has_random_access_iterator_category<_ForwardIterator2>::value &&
+                __has_random_access_iterator_category<_ForwardOutIterator>::value) {
     std::__terminate_on_exception([&] {
       std::__par_backend::__parallel_for(
           __first1,
           __last1,
           [__op, __first1, __first2, __result](_ForwardIterator1 __brick_first, _ForwardIterator1 __brick_last) {
             return std::__pstl_transform<__remove_parallel_policy_t<_ExecutionPolicy>>(
                 __cpu_backend_tag{},
                 __brick_first,
                 __brick_last,
                 __first2 + (__brick_first - __first1),
                 __result + (__brick_first - __first1),
                 __op);
           });
     });
     return __result + (__last1 - __first1);
   } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator1>::value &&
-                       __is_cpp17_random_access_iterator<_ForwardIterator2>::value &&
-                       __is_cpp17_random_access_iterator<_ForwardOutIterator>::value) {
+                       __has_random_access_iterator_category<_ForwardIterator1>::value &&
+                       __has_random_access_iterator_category<_ForwardIterator2>::value &&
+                       __has_random_access_iterator_category<_ForwardOutIterator>::value) {
     return std::__simd_walk_3(
         __first1,
         __last1 - __first1,
         __first2,
         __result,
         [&](__iter_reference<_ForwardIterator1> __in1,
             __iter_reference<_ForwardIterator2> __in2,
             __iter_reference<_ForwardOutIterator> __out_value) { __out_value = __op(__in1, __in2); });

libcxx/include/__algorithm/pstl_copy.h

 
 template <class _ExecutionPolicy,
           class _ForwardIterator,
           class _ForwardOutIterator,
           class _Size,
           enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
 copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
-  if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value)
+  if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value)
     return std::copy(__policy, __first, __first + __n, __result);
   else
     return std::copy_n(__first, __n, __result);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_COPY_H

libcxx/include/__algorithm/pstl_fill.h

template <class _ExecutionPolicy,
           class _Tp,
           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 fill_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _SizeT __n, const _Tp& __value) {
   std::__pstl_frontend_dispatch(
       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_fill_n),
       [&](_ForwardIterator __g_first, _SizeT __g_n, const _Tp& __g_value) {
-        if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value)
+        if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value)
           std::fill(__policy, __g_first, __g_first + __g_n, __g_value);
         else
           std::fill_n(__g_first, __g_n, __g_value);
       },
       std::move(__first),
       __n,
       __value);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_FILL_H

libcxx/include/__algorithm/pstl_for_each.h

template <class _ExecutionPolicy,
           class _Function,
           class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) {
   return std::__pstl_frontend_dispatch(
       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_for_each_n),
       [&](_ForwardIterator __g_first, _Size __g_size, _Function __g_func) {
-        if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+        if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value) {
           std::for_each(__policy, std::move(__g_first), __g_first + __g_size, std::move(__g_func));
         } else {
           std::for_each_n(std::move(__g_first), __g_size, std::move(__g_func));
         }
       },
       __first,
       __size,
       std::move(__func));
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
 
 #endif // _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H

libcxx/include/__algorithm/sample.h

 
 #if _LIBCPP_STD_VER >= 17
 template <class _PopulationIterator, class _SampleIterator, class _Distance,
           class _UniformRandomNumberGenerator>
 inline _LIBCPP_INLINE_VISIBILITY
 _SampleIterator sample(_PopulationIterator __first,
                        _PopulationIterator __last, _SampleIterator __output_iter,
                        _Distance __n, _UniformRandomNumberGenerator&& __g) {
-  static_assert(__is_cpp17_forward_iterator<_PopulationIterator>::value ||
-                __is_cpp17_random_access_iterator<_SampleIterator>::value,
+  static_assert(__has_forward_iterator_category<_PopulationIterator>::value ||
+                __has_random_access_iterator_category<_SampleIterator>::value,
                 "SampleIterator must meet the requirements of RandomAccessIterator");
 
   return std::__sample<_ClassicAlgPolicy>(
       std::move(__first), std::move(__last), std::move(__output_iter), __n, __g);
 }
 
 #endif // _LIBCPP_STD_VER >= 17
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___ALGORITHM_SAMPLE_H

libcxx/include/__algorithm/search.h

template <class _Iter1, class _Sent1,
           class _Proj1,
           class _Proj2>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
                                    _Iter2 __first2, _Sent2 __last2,
                                    _Pred& __pred,
                                    _Proj1& __proj1,
                                    _Proj2& __proj2,
-                                   __enable_if_t<__is_cpp17_random_access_iterator<_Iter1>::value
-                                              && __is_cpp17_random_access_iterator<_Iter2>::value>* = nullptr) {
+                                   __enable_if_t<__has_random_access_iterator_category<_Iter1>::value
+                                              && __has_random_access_iterator_category<_Iter2>::value>* = nullptr) {
 
   auto __size2 = __last2 - __first2;
   if (__size2 == 0)
     return std::make_pair(__first1, __first1);
 
   auto __size1 = __last1 - __first1;
   if (__size1 < __size2) {
     return std::make_pair(__last1, __last1);
template <class _Iter1, class _Sent1,
           class _Proj1,
           class _Proj2>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
                                    _Iter2 __first2, _Sent2 __last2,
                                    _Pred& __pred,
                                    _Proj1& __proj1,
                                    _Proj2& __proj2,
-                                   __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
-                                              && __is_cpp17_forward_iterator<_Iter2>::value
-                                              && !(__is_cpp17_random_access_iterator<_Iter1>::value
-                                                && __is_cpp17_random_access_iterator<_Iter2>::value)>* = nullptr) {
+                                   __enable_if_t<__has_forward_iterator_category<_Iter1>::value
+                                              && __has_forward_iterator_category<_Iter2>::value
+                                              && !(__has_random_access_iterator_category<_Iter1>::value
+                                                && __has_random_access_iterator_category<_Iter2>::value)>* = nullptr) {
   return std::__search_forward_impl<_ClassicAlgPolicy>(__first1, __last1,
                                                        __first2, __last2,
                                                        __pred,
                                                        __proj1,
                                                        __proj2);
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>

libcxx/include/__algorithm/search_n.h

template <class _Iter, class _Sent,
           class _Pred,
           class _Proj>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_Iter, _Iter> __search_n_impl(_Iter __first, _Sent __last,
                                    _DiffT __count,
                                    const _Type& __value,
                                    _Pred& __pred,
                                    _Proj& __proj,
-                                   __enable_if_t<__is_cpp17_random_access_iterator<_Iter>::value>* = nullptr) {
+                                   __enable_if_t<__has_random_access_iterator_category<_Iter>::value>* = nullptr) {
   return std::__search_n_random_access_impl<_ClassicAlgPolicy>(__first, __last,
                                                                __count,
                                                                __value,
                                                                __pred,
                                                                __proj,
                                                                __last - __first);
 }
 
 template <class _Iter1, class _Sent1,
           class _DiffT,
           class _Type,
           class _Pred,
           class _Proj>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 pair<_Iter1, _Iter1> __search_n_impl(_Iter1 __first, _Sent1 __last,
                                      _DiffT __count,
                                      const _Type& __value,
                                      _Pred& __pred,
                                      _Proj& __proj,
-                                     __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
-                                               && !__is_cpp17_random_access_iterator<_Iter1>::value>* = nullptr) {
+                                     __enable_if_t<__has_forward_iterator_category<_Iter1>::value
+                                               && !__has_random_access_iterator_category<_Iter1>::value>* = nullptr) {
   return std::__search_n_forward_impl<_ClassicAlgPolicy>(__first, __last,
                                                          __count,
                                                          __value,
                                                          __pred,
                                                          __proj);
 }
 
 template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>

libcxx/include/__algorithm/shift_left.h

 shift_left(_ForwardIterator __first, _ForwardIterator __last,
            typename iterator_traits<_ForwardIterator>::difference_type __n)
 {
     if (__n == 0) {
         return __last;
     }
 
     _ForwardIterator __m = __first;
-    if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+    if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value) {
         if (__n >= __last - __first) {
             return __first;
         }
         __m += __n;
     } else {
         for (; __n > 0; --__n) {
             if (__m == __last) {
                 return __first;

libcxx/include/__algorithm/shift_right.h

 _ForwardIterator
 shift_right(_ForwardIterator __first, _ForwardIterator __last,
             typename iterator_traits<_ForwardIterator>::difference_type __n)
 {
     if (__n == 0) {
         return __first;
     }
 
-    if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+    if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value) {
         decltype(__n) __d = __last - __first;
         if (__n >= __d) {
             return __last;
         }
         _ForwardIterator __m = __first + (__d - __n);
         return _VSTD::move_backward(__first, __m, __last);
-    } else if constexpr (__is_cpp17_bidirectional_iterator<_ForwardIterator>::value) {
+    } else if constexpr (__has_bidirectional_iterator_category<_ForwardIterator>::value) {
         _ForwardIterator __m = __last;
         for (; __n > 0; --__n) {
             if (__m == __first) {
                 return __last;
             }
             --__m;
         }
         return _VSTD::move_backward(__first, __m, __last);

libcxx/include/__filesystem/path.h

for (; *__e != __sentinel; ++__e)
       ;
     return __e;
   }
 
   _LIBCPP_HIDE_FROM_ABI
   static _ECharT __first_or_null(const _ECharT* __b) { return *__b; }
 };
 
-template <class _Iter, bool _IsIt = __is_cpp17_input_iterator<_Iter>::value,
+template <class _Iter, bool _IsIt = __has_input_iterator_category<_Iter>::value,
           class = void>
 struct __is_pathable_iter : false_type {};
 
 template <class _Iter>
 struct __is_pathable_iter<
     _Iter, true,
     _Void<typename __can_convert_char<
         typename iterator_traits<_Iter>::value_type>::__char_type> >

 };
 #endif // !_LIBCPP_HAS_NO_LOCALIZATION
 
 template <>
 struct _PathCVT<__path_value> {
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
-  static typename enable_if<__is_exactly_cpp17_input_iterator<_Iter>::value>::type
+  static typename enable_if<__has_exactly_input_iterator_category<_Iter>::value>::type
   __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
     for (; __b != __e; ++__b)
       __dest.push_back(*__b);
   }
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
-  static typename enable_if<__is_cpp17_forward_iterator<_Iter>::value>::type
+  static typename enable_if<__has_forward_iterator_category<_Iter>::value>::type
   __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
     __dest.append(__b, __e);
   }
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
   static void __append_range(__path_string& __dest, _Iter __b, _NullSentinel) {
     const char __sentinel = char{};
__append_string(__path_string& __dest, const basic_string<char> &__str) {
       size_t __size = __char_to_wide(__str, nullptr, 0);
       size_t __pos = __dest.size();
       __dest.resize(__pos + __size);
       __char_to_wide(__str, const_cast<__path_value*>(__dest.data()) + __pos, __size);
   }
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
-  static typename enable_if<__is_exactly_cpp17_input_iterator<_Iter>::value>::type
+  static typename enable_if<__has_exactly_input_iterator_category<_Iter>::value>::type
   __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
     basic_string<char> __tmp(__b, __e);
     __append_string(__dest, __tmp);
   }
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
-  static typename enable_if<__is_cpp17_forward_iterator<_Iter>::value>::type
+  static typename enable_if<__has_forward_iterator_category<_Iter>::value>::type
   __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
     basic_string<char> __tmp(__b, __e);
     __append_string(__dest, __tmp);
   }
 
   template <class _Iter>
   _LIBCPP_HIDE_FROM_ABI
   static void __append_range(__path_string& __dest, _Iter __b, _NullSentinel) {

libcxx/include/__iterator/advance.h

 template <
     class _InputIter, class _Distance,
     class _IntegralDistance = decltype(_VSTD::__convert_to_integral(std::declval<_Distance>())),
     class = __enable_if_t<is_integral<_IntegralDistance>::value> >
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17
 void advance(_InputIter& __i, _Distance __orig_n) {
   typedef typename iterator_traits<_InputIter>::difference_type _Difference;
   _Difference __n = static_cast<_Difference>(_VSTD::__convert_to_integral(__orig_n));
-  _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+  _LIBCPP_ASSERT(__n >= 0 || __has_bidirectional_iterator_category<_InputIter>::value,
                  "Attempt to advance(it, n) with negative n on a non-bidirectional iterator");
   _VSTD::__advance(__i, __n, typename iterator_traits<_InputIter>::iterator_category());
 }
 
 #if _LIBCPP_STD_VER >= 20
 
 // [range.iter.op.advance]
 

libcxx/include/__iterator/iterator_traits.h

 struct __has_iterator_concept_convertible_to
     : is_convertible<typename _Tp::iterator_concept, _Up>
 {};
 
 template <class _Tp, class _Up>
 struct __has_iterator_concept_convertible_to<_Tp, _Up, false> : false_type {};
 
 template <class _Tp>
-struct __is_cpp17_input_iterator : public __has_iterator_category_convertible_to<_Tp, input_iterator_tag> {};
+using __has_input_iterator_category = __has_iterator_category_convertible_to<_Tp, input_iterator_tag>;
 
 template <class _Tp>
-struct __is_cpp17_forward_iterator : public __has_iterator_category_convertible_to<_Tp, forward_iterator_tag> {};
+using __has_forward_iterator_category = __has_iterator_category_convertible_to<_Tp, forward_iterator_tag>;
 
 template <class _Tp>
-struct __is_cpp17_bidirectional_iterator : public __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag> {};
+using __has_bidirectional_iterator_category = __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>;
 
 template <class _Tp>
-struct __is_cpp17_random_access_iterator : public __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag> {};
+using __has_random_access_iterator_category = __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag>;
 
 // __is_cpp17_contiguous_iterator determines if an iterator is known by
 // libc++ to be contiguous, either because it advertises itself as such
 // (in C++20) or because it is a pointer type or a known trivial wrapper
 // around a (possibly fancy) pointer type, such as __wrap_iter<T*>.
 // Such iterators receive special "contiguous" optimizations in
 // std::copy and std::sort.
 //
 #if _LIBCPP_STD_VER >= 20
 template <class _Tp>
 struct __is_cpp17_contiguous_iterator : _Or<
     __has_iterator_category_convertible_to<_Tp, contiguous_iterator_tag>,
     __has_iterator_concept_convertible_to<_Tp, contiguous_iterator_tag>
 > {};
 #else
 template <class _Tp>
 struct __is_cpp17_contiguous_iterator : false_type {};
 #endif
 
 // Any native pointer which is an iterator is also a contiguous iterator.
 template <class _Up>
 struct __is_cpp17_contiguous_iterator<_Up*> : true_type {};
 
 
 template <class _Iter>
 class __wrap_iter;
 
 template <class _Tp>
-struct __is_exactly_cpp17_input_iterator
-    : public integral_constant<bool,
+using __has_exactly_input_iterator_category
+    = integral_constant<bool,
          __has_iterator_category_convertible_to<_Tp, input_iterator_tag>::value &&
-        !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value> {};
+        !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value>;
 
 template <class _Tp>
-struct __is_exactly_cpp17_forward_iterator
-    : public integral_constant<bool,
+using __has_exactly_forward_iterator_category
+    = integral_constant<bool,
          __has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value &&
-        !__has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>::value> {};
+        !__has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>::value>;
 
 template <class _Tp>
-struct __is_exactly_cpp17_bidirectional_iterator
-    : public integral_constant<bool,
+using __has_exactly_bidirectional_iterator_category
+    = integral_constant<bool,
          __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>::value &&
-        !__has_iterator_category_convertible_to<_Tp, random_access_iterator_tag>::value> {};
+        !__has_iterator_category_convertible_to<_Tp, random_access_iterator_tag>::value>;
 
 template<class _InputIterator>
 using __iter_value_type = typename iterator_traits<_InputIterator>::value_type;
 
 template<class _InputIterator>
 using __iter_key_type = __remove_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>;
 
 template<class _InputIterator>

libcxx/include/__iterator/move_iterator.h

#if _LIBCPP_STD_VER >= 20
     // iterator_category is inherited and not always present
     using value_type = iter_value_t<_Iter>;
     using difference_type = iter_difference_t<_Iter>;
     using pointer = _Iter;
     using reference = iter_rvalue_reference_t<_Iter>;
 #else
     typedef _Iter iterator_type;
     typedef _If<
-        __is_cpp17_random_access_iterator<_Iter>::value,
+        __has_random_access_iterator_category<_Iter>::value,
         random_access_iterator_tag,
         typename iterator_traits<_Iter>::iterator_category
     > iterator_category;
     typedef typename iterator_traits<iterator_type>::value_type value_type;
     typedef typename iterator_traits<iterator_type>::difference_type difference_type;
     typedef iterator_type pointer;
 
     typedef typename iterator_traits<iterator_type>::reference __reference;

libcxx/include/__iterator/next.h

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIter>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
+    typename enable_if<__has_input_iterator_category<_InputIter>::value, _InputIter>::type
     next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
-  _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+  _LIBCPP_ASSERT(__n >= 0 || __has_bidirectional_iterator_category<_InputIter>::value,
                  "Attempt to next(it, n) with negative n on a non-bidirectional iterator");
 
   _VSTD::advance(__x, __n);
   return __x;
 }
 
 #if _LIBCPP_STD_VER >= 20
 

libcxx/include/__iterator/prev.h

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIter>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
+    typename enable_if<__has_input_iterator_category<_InputIter>::value, _InputIter>::type
     prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
-  _LIBCPP_ASSERT(__n <= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+  _LIBCPP_ASSERT(__n <= 0 || __has_bidirectional_iterator_category<_InputIter>::value,
                  "Attempt to prev(it, n) with a positive n on a non-bidirectional iterator");
   _VSTD::advance(__x, -__n);
   return __x;
 }
 
 #if _LIBCPP_STD_VER >= 20
 
 // [range.iter.op.prev]

libcxx/include/__iterator/reverse_iterator.h

 {
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 private:
 #ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
     _Iter __t_; // no longer used as of LWG #2360, not removed due to ABI break
 #endif
 
 #if _LIBCPP_STD_VER >= 20
-    static_assert(__is_cpp17_bidirectional_iterator<_Iter>::value || bidirectional_iterator<_Iter>,
+    static_assert(__has_bidirectional_iterator_category<_Iter>::value || bidirectional_iterator<_Iter>,
         "reverse_iterator<It> requires It to be a bidirectional iterator.");
 #endif // _LIBCPP_STD_VER >= 20
 
 protected:
     _Iter current;
 public:
     using iterator_type = _Iter;
 
-    using iterator_category = _If<__is_cpp17_random_access_iterator<_Iter>::value,
+    using iterator_category = _If<__has_random_access_iterator_category<_Iter>::value,
                                   random_access_iterator_tag,
                                   typename iterator_traits<_Iter>::iterator_category>;
     using pointer = typename iterator_traits<_Iter>::pointer;
 #if _LIBCPP_STD_VER >= 20
     using iterator_concept = _If<random_access_iterator<_Iter>, random_access_iterator_tag, bidirectional_iterator_tag>;
     using value_type = iter_value_t<_Iter>;
     using difference_type = iter_difference_t<_Iter>;
     using reference = iter_reference_t<_Iter>;

 // it evaluates to false. Thus, the implementation of reverse_iterator::operator== can actually call operator== on its
 // base iterators, but the constraints on reverse_iterator::operator== prevent it from being considered during overload
 // resolution. This class simply removes the problematic constraints from comparison functions.
 template <class _Iter>
 class __unconstrained_reverse_iterator {
   _Iter __iter_;
 
 public:
-  static_assert(__is_cpp17_bidirectional_iterator<_Iter>::value || bidirectional_iterator<_Iter>);
+  static_assert(__has_bidirectional_iterator_category<_Iter>::value || bidirectional_iterator<_Iter>);
 
   using iterator_type = _Iter;
   using iterator_category =
-      _If<__is_cpp17_random_access_iterator<_Iter>::value, random_access_iterator_tag, __iterator_category_type<_Iter>>;
+      _If<__has_random_access_iterator_category<_Iter>::value, random_access_iterator_tag, __iterator_category_type<_Iter>>;
   using pointer = __iterator_pointer_type<_Iter>;
   using value_type = iter_value_t<_Iter>;
   using difference_type = iter_difference_t<_Iter>;
   using reference = iter_reference_t<_Iter>;
 
   _LIBCPP_HIDE_FROM_ABI constexpr __unconstrained_reverse_iterator() = default;
   _LIBCPP_HIDE_FROM_ABI constexpr __unconstrained_reverse_iterator(const __unconstrained_reverse_iterator&) = default;
   _LIBCPP_HIDE_FROM_ABI constexpr explicit __unconstrained_reverse_iterator(_Iter __iter) : __iter_(__iter) {}

libcxx/include/__memory/uninitialized_algorithms.h

 // TODO: Rewrite this to iterate left to right and use reverse_iterators when calling
 // Destroys every element in the range [first, last) FROM RIGHT TO LEFT using allocator
 // destruction. If elements are themselves C-style arrays, they are recursively destroyed
 // in the same manner.
 //
 // This function assumes that destructors do not throw, and that the allocator is bound to
 // the correct type.
 template<class _Alloc, class _BidirIter, class = __enable_if_t<
-    __is_cpp17_bidirectional_iterator<_BidirIter>::value
+    __has_bidirectional_iterator_category<_BidirIter>::value
 >>
 _LIBCPP_HIDE_FROM_ABI
 constexpr void __allocator_destroy_multidimensional(_Alloc& __alloc, _BidirIter __first, _BidirIter __last) noexcept {
     using _ValueType = typename iterator_traits<_BidirIter>::value_type;
     static_assert(is_same_v<typename allocator_traits<_Alloc>::value_type, _ValueType>,
         "The allocator should already be rebound to the correct type");
 
     if (__first == __last)

libcxx/include/__ranges/join_view.h

inline namespace __cpo {
   inline constexpr auto join = __join_view::__fn{};
 } // namespace __cpo
 } // namespace views
 } // namespace ranges
 
 template <class _JoinViewIterator>
   requires(_JoinViewIterator::__is_join_view_iterator &&
            ranges::common_range<typename _JoinViewIterator::_Parent> &&
-           __is_cpp17_random_access_iterator<typename _JoinViewIterator::_Outer>::value &&
-           __is_cpp17_random_access_iterator<typename _JoinViewIterator::_Inner>::value)
+           __has_random_access_iterator_category<typename _JoinViewIterator::_Outer>::value &&
+           __has_random_access_iterator_category<typename _JoinViewIterator::_Inner>::value)
 struct __segmented_iterator_traits<_JoinViewIterator> {
 
   using __segment_iterator =
       _LIBCPP_NODEBUG __iterator_with_data<typename _JoinViewIterator::_Outer, typename _JoinViewIterator::_Parent*>;
   using __local_iterator = typename _JoinViewIterator::_Inner;
 
   // TODO: Would it make sense to enable the optimization for other iterator types?
 

libcxx/include/__split_buffer

public:
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_front() { __destruct_at_begin(__begin_ + 1); }
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_back() { __destruct_at_end(__end_ - 1); }
 
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n);
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n, const_reference __x);
 
   template <class _InputIter>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-      __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value>
+      __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value>
       __construct_at_end(_InputIter __first, _InputIter __last);
 
   template <class _ForwardIterator>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value>
+      __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value>
       __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);
 
   template <class _Iterator, class _Sentinel>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
   void __construct_at_end_with_sentinel(_Iterator __first, _Sentinel __last);
 
   template <class _Iterator>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x)
     for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
         __alloc_traits::construct(this->__alloc(),
             _VSTD::__to_address(__tx.__pos_), __x);
     }
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIter>
-_LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value>
+_LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value>
 __split_buffer<_Tp, _Allocator>::__construct_at_end(_InputIter __first, _InputIter __last)
 {
   __construct_at_end_with_sentinel(__first, __last);
 }
 
 template <class _Tp, class _Allocator>
 template <class _Iterator, class _Sentinel>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
for (; __first != __last; ++__first)
             swap(__buf);
         }
         __alloc_traits::construct(__a, _VSTD::__to_address(this->__end_), *__first);
         ++this->__end_;
     }
 }
 template <class _Tp, class _Allocator>
 template <class _ForwardIterator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value>
+_LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value>
 __split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last)
 {
   __construct_at_end_with_size(__first, std::distance(__first, __last));
 }
 
 template <class _Tp, class _Allocator>
 template <class _ForwardIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20

libcxx/include/__tree

 template <class _ForwardIterator>
 void
 __tree<_Tp, _Compare, _Allocator>::__assign_unique(_ForwardIterator __first, _ForwardIterator __last)
 {
     typedef iterator_traits<_ForwardIterator> _ITraits;
     typedef typename _ITraits::value_type _ItValueType;
     static_assert((is_same<_ItValueType, __container_value_type>::value),
                   "__assign_unique may only be called with the containers value type");
-    static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+    static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
                   "__assign_unique requires a forward iterator");
     if (size() != 0)
     {
         _DetachedTreeCache __cache(this);
           for (; __cache.__get() != nullptr && __first != __last; ++__first) {
               if (__node_assign_unique(*__first, __cache.__get()).second)
                   __cache.__advance();
             }

libcxx/include/deque

_LIBCPP_HIDE_FROM_ABI deque(size_type __n, const value_type& __v, const allocator_type& __a)
         : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a)
     {
         if (__n > 0)
             __append(__n, __v);
     }
 
     template <class _InputIter>
     _LIBCPP_HIDE_FROM_ABI deque(_InputIter __f, _InputIter __l,
-              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type* = 0);
+              typename enable_if<__has_input_iterator_category<_InputIter>::value>::type* = 0);
     template <class _InputIter>
     _LIBCPP_HIDE_FROM_ABI deque(_InputIter __f, _InputIter __l, const allocator_type& __a,
-              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type* = 0);
+              typename enable_if<__has_input_iterator_category<_InputIter>::value>::type* = 0);
 
 #if _LIBCPP_STD_VER >= 23
   template <_ContainerCompatibleRange<_Tp> _Range>
   _LIBCPP_HIDE_FROM_ABI deque(from_range_t, _Range&& __range,
       const allocator_type& __a = allocator_type())
     : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
     if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
       __append_with_size(ranges::begin(__range), ranges::distance(__range));
deque& operator=(deque&& __c)
                    is_nothrow_move_assignable<allocator_type>::value);
 
     _LIBCPP_HIDE_FROM_ABI
     void assign(initializer_list<value_type> __il) {assign(__il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
 
     template <class _InputIter>
     _LIBCPP_HIDE_FROM_ABI void assign(_InputIter __f, _InputIter __l,
-                    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value &&
-                                      !__is_cpp17_random_access_iterator<_InputIter>::value>::type* = 0);
+                    typename enable_if<__has_input_iterator_category<_InputIter>::value &&
+                                      !__has_random_access_iterator_category<_InputIter>::value>::type* = 0);
     template <class _RAIter>
     _LIBCPP_HIDE_FROM_ABI void assign(_RAIter __f, _RAIter __l,
-                    typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+                    typename enable_if<__has_random_access_iterator_category<_RAIter>::value>::type* = 0);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<_Tp> _Range>
     _LIBCPP_HIDE_FROM_ABI
     void assign_range(_Range&& __range) {
       if constexpr (ranges::random_access_range<_Range>) {
         auto __n = static_cast<size_type>(ranges::distance(__range));
         __assign_with_size_random_access(ranges::begin(__range), __n);
#endif
     _LIBCPP_HIDE_FROM_ABI
     iterator insert(const_iterator __p, initializer_list<value_type> __il)
         {return insert(__p, __il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __v);
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __v);
     template <class _InputIter>
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _InputIter __f, _InputIter __l,
-                         typename enable_if<__is_exactly_cpp17_input_iterator<_InputIter>::value>::type* = 0);
+                         typename enable_if<__has_exactly_input_iterator_category<_InputIter>::value>::type* = 0);
     template <class _ForwardIterator>
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l,
-                        typename enable_if<__is_exactly_cpp17_forward_iterator<_ForwardIterator>::value>::type* = 0);
+                        typename enable_if<__has_exactly_forward_iterator_category<_ForwardIterator>::value>::type* = 0);
     template <class _BiIter>
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _BiIter __f, _BiIter __l,
-                         typename enable_if<__is_cpp17_bidirectional_iterator<_BiIter>::value>::type* = 0);
+                         typename enable_if<__has_bidirectional_iterator_category<_BiIter>::value>::type* = 0);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<_Tp> _Range>
     _LIBCPP_HIDE_FROM_ABI
     iterator insert_range(const_iterator __position, _Range&& __range) {
       if constexpr (ranges::bidirectional_range<_Range>) {
         auto __n = static_cast<size_type>(ranges::distance(__range));
         return __insert_bidirectional(__position, ranges::begin(__range), ranges::end(__range), __n);
private:
     _LIBCPP_HIDE_FROM_ABI
     iterator __insert_bidirectional(const_iterator __p, _BiIter __f, _Sentinel __sent, size_type __n);
     template <class _BiIter>
     _LIBCPP_HIDE_FROM_ABI
     iterator __insert_bidirectional(const_iterator __p, _BiIter __f, _BiIter __l, size_type __n);
 
     template <class _InpIter>
     _LIBCPP_HIDE_FROM_ABI void __append(_InpIter __f, _InpIter __l,
-                 typename enable_if<__is_exactly_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+                 typename enable_if<__has_exactly_input_iterator_category<_InpIter>::value>::type* = 0);
     template <class _ForIter>
     _LIBCPP_HIDE_FROM_ABI void __append(_ForIter __f, _ForIter __l,
-                      typename enable_if<__is_cpp17_forward_iterator<_ForIter>::value>::type* = 0);
+                      typename enable_if<__has_forward_iterator_category<_ForIter>::value>::type* = 0);
 
     template <class _InputIterator>
     _LIBCPP_HIDE_FROM_ABI void __append_with_size(_InputIterator __from, size_type __n);
     template <class _InputIterator, class _Sentinel>
     _LIBCPP_HIDE_FROM_ABI void __append_with_sentinel(_InputIterator __f, _Sentinel __l);
 
     _LIBCPP_HIDE_FROM_ABI void __append(size_type __n);
     _LIBCPP_HIDE_FROM_ABI void __append(size_type __n, const value_type& __v);

 
 template <class _Tp, class _Alloc>
 _LIBCPP_CONSTEXPR const typename allocator_traits<_Alloc>::difference_type deque<_Tp, _Alloc>::__block_size =
     __deque_block_size<value_type, difference_type>::value;
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 deque(_InputIterator, _InputIterator)
   -> deque<__iter_value_type<_InputIterator>, _Alloc>;
 
 template<class _InputIterator,
          class _Alloc,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 deque(_InputIterator, _InputIterator, _Alloc)
   -> deque<__iter_value_type<_InputIterator>, _Alloc>;
 #endif
 
 #if _LIBCPP_STD_VER >= 23
 template <ranges::input_range _Range,

 {
     if (__n > 0)
         __append(__n, __v);
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIter>
 deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l,
-              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type*)
+              typename enable_if<__has_input_iterator_category<_InputIter>::value>::type*)
     : __start_(0), __size_(0, __default_init_tag())
 {
     __append(__f, __l);
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIter>
 deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l, const allocator_type& __a,
-              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type*)
+              typename enable_if<__has_input_iterator_category<_InputIter>::value>::type*)
     : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a)
 {
     __append(__f, __l);
 }
 
 template <class _Tp, class _Allocator>
 deque<_Tp, _Allocator>::deque(const deque& __c)
     : __map_(__pointer_allocator(__alloc_traits::select_on_container_copy_construction(__c.__alloc()))),

 }
 
 #endif // _LIBCPP_CXX03_LANG
 
 template <class _Tp, class _Allocator>
 template <class _InputIter>
 void
 deque<_Tp, _Allocator>::assign(_InputIter __f, _InputIter __l,
-                               typename enable_if<__is_cpp17_input_iterator<_InputIter>::value &&
-                                                 !__is_cpp17_random_access_iterator<_InputIter>::value>::type*)
+                               typename enable_if<__has_input_iterator_category<_InputIter>::value &&
+                                                 !__has_random_access_iterator_category<_InputIter>::value>::type*)
 {
   __assign_with_sentinel(__f, __l);
 }
 
 template <class _Tp, class _Allocator>
 template <class _Iterator, class _Sentinel>
 _LIBCPP_HIDE_FROM_ABI
 void deque<_Tp, _Allocator>::__assign_with_sentinel(_Iterator __f, _Sentinel __l) {
     iterator __i = begin();
     iterator __e = end();
     for (; __f != __l && __i != __e; ++__f, (void) ++__i)
         *__i = *__f;
     if (__f != __l)
         __append_with_sentinel(std::move(__f), std::move(__l));
     else
         __erase_to_end(__i);
 }
 
 template <class _Tp, class _Allocator>
 template <class _RAIter>
 void
 deque<_Tp, _Allocator>::assign(_RAIter __f, _RAIter __l,
-                               typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+                               typename enable_if<__has_random_access_iterator_category<_RAIter>::value>::type*)
 {
   __assign_with_size_random_access(__f, __l - __f);
 }
 
 template <class _Tp, class _Allocator>
 template <class _RandomAccessIterator>
 _LIBCPP_HIDE_FROM_ABI
 void deque<_Tp, _Allocator>::__assign_with_size_random_access(_RandomAccessIterator __f, difference_type __n) {
deque<_Tp, _Allocator>::insert(const_iterator __p, size_type __n, const value_type& __v)
     }
     return begin() + __pos;
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIter>
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::insert(const_iterator __p, _InputIter __f, _InputIter __l,
-                               typename enable_if<__is_exactly_cpp17_input_iterator<_InputIter>::value>::type*)
+                               typename enable_if<__has_exactly_input_iterator_category<_InputIter>::value>::type*)
 {
   return __insert_with_sentinel(__p, __f, __l);
 }
 
 template <class _Tp, class _Allocator>
 template <class _Iterator, class _Sentinel>
 _LIBCPP_HIDE_FROM_ABI
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::__insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l) {
     __split_buffer<value_type, allocator_type&> __buf(__alloc());
     __buf.__construct_at_end_with_sentinel(std::move(__f), std::move(__l));
     typedef typename __split_buffer<value_type, allocator_type&>::iterator __bi;
     return insert(__p, move_iterator<__bi>(__buf.begin()), move_iterator<__bi>(__buf.end()));
 }
 
 template <class _Tp, class _Allocator>
 template <class _ForwardIterator>
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l,
-                               typename enable_if<__is_exactly_cpp17_forward_iterator<_ForwardIterator>::value>::type*)
+                               typename enable_if<__has_exactly_forward_iterator_category<_ForwardIterator>::value>::type*)
 {
   return __insert_with_size(__p, __f, std::distance(__f, __l));
 }
 
 template <class _Tp, class _Allocator>
 template <class _Iterator>
 _LIBCPP_HIDE_FROM_ABI
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::__insert_with_size(const_iterator __p, _Iterator __f, size_type __n) {
     __split_buffer<value_type, allocator_type&> __buf(__n, 0, __alloc());
     __buf.__construct_at_end_with_size(__f, __n);
     typedef typename __split_buffer<value_type, allocator_type&>::iterator __fwd;
     return insert(__p, move_iterator<__fwd>(__buf.begin()), move_iterator<__fwd>(__buf.end()));
 }
 
 template <class _Tp, class _Allocator>
 template <class _BiIter>
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::insert(const_iterator __p, _BiIter __f, _BiIter __l,
-                               typename enable_if<__is_cpp17_bidirectional_iterator<_BiIter>::value>::type*)
+                               typename enable_if<__has_bidirectional_iterator_category<_BiIter>::value>::type*)
 {
   return __insert_bidirectional(__p, __f, __l, std::distance(__f, __l));
 }
 
 template <class _Tp, class _Allocator>
 template <class _BiIter, class _Sentinel>
 _LIBCPP_HIDE_FROM_ABI
 typename deque<_Tp, _Allocator>::iterator
deque<_Tp, _Allocator>::__insert_bidirectional(const_iterator __p, _BiIter __f, _BiIter __l, size_type __n) {
     }
     return begin() + __pos;
 }
 
 template <class _Tp, class _Allocator>
 template <class _InpIter>
 void
 deque<_Tp, _Allocator>::__append(_InpIter __f, _InpIter __l,
-                                 typename enable_if<__is_exactly_cpp17_input_iterator<_InpIter>::value>::type*)
+                                 typename enable_if<__has_exactly_input_iterator_category<_InpIter>::value>::type*)
 {
   __append_with_sentinel(__f, __l);
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIterator, class _Sentinel>
 _LIBCPP_HIDE_FROM_ABI
 void deque<_Tp, _Allocator>::__append_with_sentinel(_InputIterator __f, _Sentinel __l) {
     for (; __f != __l; ++__f)
 #ifdef _LIBCPP_CXX03_LANG
         push_back(*__f);
 #else
         emplace_back(*__f);
 #endif
 }
 
 template <class _Tp, class _Allocator>
 template <class _ForIter>
 void
 deque<_Tp, _Allocator>::__append(_ForIter __f, _ForIter __l,
-                                 typename enable_if<__is_cpp17_forward_iterator<_ForIter>::value>::type*)
+                                 typename enable_if<__has_forward_iterator_category<_ForIter>::value>::type*)
 {
     __append_with_size(__f, std::distance(__f, __l));
 }
 
 template <class _Tp, class _Allocator>
 template <class _InputIterator>
 _LIBCPP_HIDE_FROM_ABI
 void deque<_Tp, _Allocator>::__append_with_size(_InputIterator __f, size_type __n) {

libcxx/include/forward_list

#endif
     template <class = __enable_if_t<__is_allocator<_Alloc>::value> >
     _LIBCPP_HIDE_FROM_ABI forward_list(size_type __n, const value_type& __v, const allocator_type& __a) : base(__a)
     {
         insert_after(cbefore_begin(), __n, __v);
     }
 
     template <class _InputIterator>
     _LIBCPP_HIDE_FROM_ABI forward_list(_InputIterator __f, _InputIterator __l,
-                     __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>* = nullptr);
+                     __enable_if_t<__has_input_iterator_category<_InputIterator>::value>* = nullptr);
     template <class _InputIterator>
     _LIBCPP_HIDE_FROM_ABI forward_list(_InputIterator __f, _InputIterator __l,
                      const allocator_type& __a,
-                     __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>* = nullptr);
+                     __enable_if_t<__has_input_iterator_category<_InputIterator>::value>* = nullptr);
     _LIBCPP_HIDE_FROM_ABI forward_list(const forward_list& __x);
     _LIBCPP_HIDE_FROM_ABI forward_list(const forward_list& __x, const __type_identity_t<allocator_type>& __a);
 
     _LIBCPP_HIDE_FROM_ABI forward_list& operator=(const forward_list& __x);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_INLINE_VISIBILITY
     forward_list(forward_list&& __x)
#ifndef _LIBCPP_CXX03_LANG
 
     _LIBCPP_INLINE_VISIBILITY
     void assign(initializer_list<value_type> __il);
 #endif // _LIBCPP_CXX03_LANG
 
     // ~forward_list() = default;
 
     template <class _InputIterator>
-    __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>
+    __enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>
     _LIBCPP_HIDE_FROM_ABI assign(_InputIterator __f, _InputIterator __l);
     _LIBCPP_HIDE_FROM_ABI void assign(size_type __n, const value_type& __v);
 
     _LIBCPP_INLINE_VISIBILITY
     allocator_type get_allocator() const _NOEXCEPT
         {return allocator_type(base::__alloc());}
 
     _LIBCPP_INLINE_VISIBILITY
#ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, value_type&& __v);
     _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, initializer_list<value_type> __il)
         {return insert_after(__p, __il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, const value_type& __v);
     _LIBCPP_HIDE_FROM_ABI iterator insert_after(const_iterator __p, size_type __n, const value_type& __v);
     template <class _InputIterator>
     _LIBCPP_INLINE_VISIBILITY
-    __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, iterator>
+    __enable_if_t<__has_input_iterator_category<_InputIterator>::value, iterator>
         insert_after(const_iterator __p, _InputIterator __f, _InputIterator __l);
 
     _LIBCPP_HIDE_FROM_ABI iterator erase_after(const_iterator __p);
     _LIBCPP_HIDE_FROM_ABI iterator erase_after(const_iterator __f, const_iterator __l);
 
     _LIBCPP_INLINE_VISIBILITY
     void swap(forward_list& __x)
 #if _LIBCPP_STD_VER >= 14
static _LIBCPP_HIDDEN
         __node_pointer
         __sort(__node_pointer __f, difference_type __sz, _Compare& __comp);
 };
 
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 forward_list(_InputIterator, _InputIterator)
   -> forward_list<__iter_value_type<_InputIterator>, _Alloc>;
 
 template<class _InputIterator,
          class _Alloc,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 forward_list(_InputIterator, _InputIterator, _Alloc)
   -> forward_list<__iter_value_type<_InputIterator>, _Alloc>;
 #endif
 
 template <class _Tp, class _Alloc>
 inline

 forward_list<_Tp, _Alloc>::forward_list(size_type __n, const value_type& __v)
 {
     insert_after(cbefore_begin(), __n, __v);
 }
 
 template <class _Tp, class _Alloc>
 template <class _InputIterator>
 forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
-                                        __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>*)
+                                        __enable_if_t<__has_input_iterator_category<_InputIterator>::value>*)
 {
     insert_after(cbefore_begin(), __f, __l);
 }
 
 template <class _Tp, class _Alloc>
 template <class _InputIterator>
 forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
                                         const allocator_type& __a,
-                                        __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>*)
+                                        __enable_if_t<__has_input_iterator_category<_InputIterator>::value>*)
     : base(__a)
 {
     insert_after(cbefore_begin(), __f, __l);
 }
 
 template <class _Tp, class _Alloc>
 forward_list<_Tp, _Alloc>::forward_list(const forward_list& __x)
     : base(
forward_list<_Tp, _Alloc>::operator=(initializer_list<value_type> __il)
     assign(__il.begin(), __il.end());
     return *this;
 }
 
 #endif // _LIBCPP_CXX03_LANG
 
 template <class _Tp, class _Alloc>
 template <class _InputIterator>
-__enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>
+__enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>
 forward_list<_Tp, _Alloc>::assign(_InputIterator __f, _InputIterator __l)
 {
     iterator __i = before_begin();
     iterator __j = _VSTD::next(__i);
     iterator __e = end();
     for (; __j != __e && __f != __l; ++__i, (void) ++__j, ++__f)
         *__j = *__f;
     if (__j == __e)
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
         __r->__next_ = __first;
         __r = static_cast<__begin_node_pointer>(__last);
     }
     return iterator(__r);
 }
 
 template <class _Tp, class _Alloc>
 template <class _InputIterator>
-__enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, typename forward_list<_Tp, _Alloc>::iterator>
+__enable_if_t<__has_input_iterator_category<_InputIterator>::value, typename forward_list<_Tp, _Alloc>::iterator>
 forward_list<_Tp, _Alloc>::insert_after(const_iterator __p,
                                         _InputIterator __f, _InputIterator __l)
 {
     __begin_node_pointer __r = __p.__get_begin();
     if (__f != __l)
     {
         __node_allocator& __a = base::__alloc();
         typedef __allocator_destructor<__node_allocator> _Dp;

libcxx/include/list

#endif
     {
         _VSTD::__debug_db_insert_c(this);
         for (; __n > 0; --__n)
             push_back(__x);
     }
 
     template <class _InpIter>
     _LIBCPP_HIDE_FROM_ABI list(_InpIter __f, _InpIter __l,
-             __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>* = 0);
+             __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
     template <class _InpIter>
     _LIBCPP_HIDE_FROM_ABI list(_InpIter __f, _InpIter __l, const allocator_type& __a,
-             __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>* = 0);
+             __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
 
     _LIBCPP_HIDE_FROM_ABI list(const list& __c);
     _LIBCPP_HIDE_FROM_ABI list(const list& __c, const __type_identity_t<allocator_type>& __a);
     _LIBCPP_INLINE_VISIBILITY
     list& operator=(const list& __c);
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il);
     _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il, const allocator_type& __a);
#ifndef _LIBCPP_CXX03_LANG
 
     _LIBCPP_INLINE_VISIBILITY
     void assign(initializer_list<value_type> __il)
         {assign(__il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
 
     template <class _InpIter>
     _LIBCPP_HIDE_FROM_ABI void assign(_InpIter __f, _InpIter __l,
-                    __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>* = 0);
+                    __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
     _LIBCPP_HIDE_FROM_ABI void assign(size_type __n, const value_type& __x);
 
     _LIBCPP_INLINE_VISIBILITY
     allocator_type get_allocator() const _NOEXCEPT;
 
     _LIBCPP_INLINE_VISIBILITY
     size_type size() const _NOEXCEPT     {return base::__sz();}
     _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
#else
     _LIBCPP_INLINE_VISIBILITY
     void __emplace_back(value_type const& __arg) { push_back(__arg); }
 #endif
 
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x);
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __x);
     template <class _InpIter>
     _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _InpIter __f, _InpIter __l,
-                        __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>* = 0);
+                        __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
 
     _LIBCPP_INLINE_VISIBILITY
     void swap(list& __c)
 #if _LIBCPP_STD_VER >= 14
         _NOEXCEPT
 #else
         _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||
                    __is_nothrow_swappable<__node_allocator>::value)
private:
     _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, true_type)
         _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
     _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, false_type);
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 list(_InputIterator, _InputIterator)
   -> list<__iter_value_type<_InputIterator>, _Alloc>;
 
 template<class _InputIterator,
          class _Alloc,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 list(_InputIterator, _InputIterator, _Alloc)
   -> list<__iter_value_type<_InputIterator>, _Alloc>;
 #endif
 
 // Link in nodes [__f, __l] just prior to __p
 template <class _Tp, class _Alloc>
list<_Tp, _Alloc>::list(size_type __n, const value_type& __x)
     _VSTD::__debug_db_insert_c(this);
     for (; __n > 0; --__n)
         push_back(__x);
 }
 
 template <class _Tp, class _Alloc>
 template <class _InpIter>
 list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l,
-                        __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>*)
+                        __enable_if_t<__has_input_iterator_category<_InpIter>::value>*)
 {
     _VSTD::__debug_db_insert_c(this);
     for (; __f != __l; ++__f)
         __emplace_back(*__f);
 }
 
 template <class _Tp, class _Alloc>
 template <class _InpIter>
 list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a,
-                        __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>*)
+                        __enable_if_t<__has_input_iterator_category<_InpIter>::value>*)
     : base(__a)
 {
     _VSTD::__debug_db_insert_c(this);
     for (; __f != __l; ++__f)
         __emplace_back(*__f);
 }
 
 template <class _Tp, class _Alloc>
list<_Tp, _Alloc>::operator=(const list& __c)
     }
     return *this;
 }
 
 template <class _Tp, class _Alloc>
 template <class _InpIter>
 void
 list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l,
-                          __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>*)
+                          __enable_if_t<__has_input_iterator_category<_InpIter>::value>*)
 {
     iterator __i = begin();
     iterator __e = end();
     for (; __f != __l && __i != __e; ++__f, (void) ++__i)
         *__i = *__f;
     if (__i == __e)
         insert(__e, __f, __l);
     else
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
     }
     return __r;
 }
 
 template <class _Tp, class _Alloc>
 template <class _InpIter>
 typename list<_Tp, _Alloc>::iterator
 list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,
-                          __enable_if_t<__is_cpp17_input_iterator<_InpIter>::value>*)
+                          __enable_if_t<__has_input_iterator_category<_InpIter>::value>*)
 {
     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
                          "list::insert(iterator, range) called with an iterator not referring to this list");
     iterator __r(__p.__ptr_, this);
     if (__f != __l)
     {
         size_type __ds = 0;
         __node_allocator& __na = base::__node_alloc();

libcxx/include/map

 #ifdef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node_with_key(const key_type& __k);
 #endif
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 map(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
   -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
 
 template<class _Key, class _Tp, class _Compare = less<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 map(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
   -> map<remove_const_t<_Key>, _Tp, _Compare, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 map(_InputIterator, _InputIterator, _Allocator)
   -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
          less<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Tp, class _Allocator,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 map(initializer_list<pair<_Key, _Tp>>, _Allocator)
private:
 
     typedef __map_node_destructor<__node_allocator> _Dp;
     typedef unique_ptr<__node, _Dp> __node_holder;
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multimap(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
   -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
 
 template<class _Key, class _Tp, class _Compare = less<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multimap(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
   -> multimap<remove_const_t<_Key>, _Tp, _Compare, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multimap(_InputIterator, _InputIterator, _Allocator)
   -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
          less<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Tp, class _Allocator,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)

libcxx/include/queue

queue()
         _NOEXCEPT_(is_nothrow_default_constructible<container_type>::value)
         : c() {}
 
     _LIBCPP_INLINE_VISIBILITY
     queue(const queue& __q) : c(__q.c) {}
 
 #if _LIBCPP_STD_VER >= 23
     template <class _InputIterator,
-              class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>>
+              class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>>
     _LIBCPP_HIDE_FROM_ABI
     queue(_InputIterator __first, _InputIterator __last) : c(__first, __last) {}
 
     template <class _InputIterator,
               class _Alloc,
-              class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+              class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
               class = __enable_if_t<uses_allocator<container_type, _Alloc>::value>>
     _LIBCPP_HIDE_FROM_ABI
     queue(_InputIterator __first, _InputIterator __second, const _Alloc& __alloc) : c(__first, __second, __alloc) {}
 #endif
 
     _LIBCPP_INLINE_VISIBILITY
     queue& operator=(const queue& __q) {c = __q.c; return *this;}
 
template<class _Container,
          class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
 >
 queue(_Container, _Alloc)
     -> queue<typename _Container::value_type, _Container>;
 #endif
 
 #if _LIBCPP_STD_VER >= 23
 template <class _InputIterator,
-          class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>>
+          class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>>
 queue(_InputIterator, _InputIterator)
     -> queue<__iter_value_type<_InputIterator>>;
 
 template <class _InputIterator,
           class _Alloc,
-          class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+          class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
           class = __enable_if_t<__is_allocator<_Alloc>::value>>
 queue(_InputIterator, _InputIterator, _Alloc)
     -> queue<__iter_value_type<_InputIterator>, deque<__iter_value_type<_InputIterator>, _Alloc>>;
 #endif
 
 template <class _Tp, class _Container>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
#endif // _LIBCPP_CXX03_LANG
     explicit priority_queue(const value_compare& __comp)
         : c(), comp(__comp) {}
     _LIBCPP_INLINE_VISIBILITY
     priority_queue(const value_compare& __comp, const container_type& __c);
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_INLINE_VISIBILITY
     priority_queue(const value_compare& __comp, container_type&& __c);
 #endif
-    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp = value_compare());
-    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp, const container_type& __c);
 #ifndef _LIBCPP_CXX03_LANG
-    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp, container_type&& __c);
 #endif // _LIBCPP_CXX03_LANG
     template <class _Alloc>
         _LIBCPP_INLINE_VISIBILITY
         explicit priority_queue(const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
template <class _Alloc>
                        const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
     template <class _Alloc>
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(priority_queue&& __q, const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
 #endif // _LIBCPP_CXX03_LANG
 
-    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l, const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
 
-    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp, const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
 
-    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp, const container_type& __c, const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
 
 #ifndef _LIBCPP_CXX03_LANG
-    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__has_input_iterator_category<_InputIter>::value> >
         _LIBCPP_INLINE_VISIBILITY
         priority_queue(_InputIter __f, _InputIter __l,
                        const value_compare& __comp, container_type&& __c, const _Alloc& __a,
                        __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
 #endif  // _LIBCPP_CXX03_LANG
 
     _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
     bool            empty() const {return c.empty();}
template <class _Compare,
           class = enable_if_t<!__is_allocator<_Container>::value>
 >
 priority_queue(_Compare, _Container)
     -> priority_queue<typename _Container::value_type, _Container, _Compare>;
 
 template<class _InputIterator,
          class _Compare = less<__iter_value_type<_InputIterator>>,
          class _Container = vector<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Compare>::value>,
          class = enable_if_t<!__is_allocator<_Container>::value>
 >
 priority_queue(_InputIterator, _InputIterator, _Compare = _Compare(), _Container = _Container())
     -> priority_queue<__iter_value_type<_InputIterator>, _Container, _Compare>;
 
 template<class _Compare,
          class _Container,
          class _Alloc,
          class = enable_if_t<!__is_allocator<_Compare>::value>,
          class = enable_if_t<!__is_allocator<_Container>::value>,
          class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
 >
 priority_queue(_Compare, _Container, _Alloc)
     -> priority_queue<typename _Container::value_type, _Container, _Compare>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>
 >
 priority_queue(_InputIterator, _InputIterator, _Allocator)
     -> priority_queue<__iter_value_type<_InputIterator>,
                       vector<__iter_value_type<_InputIterator>, _Allocator>,
                       less<__iter_value_type<_InputIterator>>>;
 
 template<class _InputIterator, class _Compare, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Compare>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>
 >
 priority_queue(_InputIterator, _InputIterator, _Compare, _Allocator)
     -> priority_queue<__iter_value_type<_InputIterator>,
                       vector<__iter_value_type<_InputIterator>, _Allocator>, _Compare>;
 
 template<class _InputIterator, class _Compare, class _Container, class _Alloc,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Compare>::value>,
          class = enable_if_t<!__is_allocator<_Container>::value>,
          class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
 >
 priority_queue(_InputIterator, _InputIterator, _Compare, _Container, _Alloc)
     -> priority_queue<typename _Container::value_type, _Container, _Compare>;
 #endif
 

libcxx/include/regex

#endif
     template <class _ST, class _SA>
         _LIBCPP_INLINE_VISIBILITY
         basic_regex& assign(const basic_string<value_type, _ST, _SA>& __s,
                             flag_type __f = regex_constants::ECMAScript)
             {return assign(__s.begin(), __s.end(), __f);}
 
     template <class _InputIterator>
         _LIBCPP_INLINE_VISIBILITY
-        typename enable_if<__is_exactly_cpp17_input_iterator<_InputIterator>::value, basic_regex&>::type
+        typename enable_if<__has_exactly_input_iterator_category<_InputIterator>::value, basic_regex&>::type
         assign(_InputIterator __first, _InputIterator __last,
                             flag_type __f = regex_constants::ECMAScript)
         {
             basic_string<_CharT> __t(__first, __last);
             return assign(__t.begin(), __t.end(), __f);
         }
 
 private:
     _LIBCPP_INLINE_VISIBILITY
     void __member_init(flag_type __f)
     {
         __flags_ = __f;
         __marked_count_ = 0;
         __loop_count_ = 0;
         __open_count_ = 0;
         __end_ = nullptr;
     }
 public:
 
     template <class _ForwardIterator>
         _LIBCPP_INLINE_VISIBILITY
         typename enable_if
         <
-            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            __has_forward_iterator_category<_ForwardIterator>::value,
             basic_regex&
         >::type
         assign(_ForwardIterator __first, _ForwardIterator __last,
                             flag_type __f = regex_constants::ECMAScript)
         {
             return assign(basic_regex(__first, __last, __f));
         }
 
regex_search(__wrap_iter<_Iter> __first,
                  const basic_regex<_Cp, _Tp>& __e,
                  regex_constants::match_flag_type __flags);
 
     template <class, class> friend class __lookahead;
 };
 
 #if _LIBCPP_STD_VER >= 17
 template <class _ForwardIterator,
-          class = typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value, nullptr_t>::type
+          class = typename enable_if<__has_forward_iterator_category<_ForwardIterator>::value, nullptr_t>::type
 >
 basic_regex(_ForwardIterator, _ForwardIterator,
             regex_constants::syntax_option_type = regex_constants::ECMAScript)
     -> basic_regex<typename iterator_traits<_ForwardIterator>::value_type>;
 #endif
 
 template <class _CharT, class _Traits>
     const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::icase;

libcxx/include/set

#if _LIBCPP_STD_VER >= 14
     equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
 #endif
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Compare = less<__iter_value_type<_InputIterator>>,
          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>>
 set(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
   -> set<__iter_value_type<_InputIterator>, _Compare, _Allocator>;
 
 template<class _Key, class _Compare = less<_Key>,
          class _Allocator = allocator<_Key>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 set(initializer_list<_Key>, _Compare = _Compare(), _Allocator = _Allocator())
   -> set<_Key, _Compare, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 set(_InputIterator, _InputIterator, _Allocator)
   -> set<__iter_value_type<_InputIterator>,
          less<__iter_value_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Allocator,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 set(initializer_list<_Key>, _Allocator)
#if _LIBCPP_STD_VER >= 14
     equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
 #endif
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Compare = less<__iter_value_type<_InputIterator>>,
          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>>
 multiset(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
   -> multiset<__iter_value_type<_InputIterator>, _Compare, _Allocator>;
 
 template<class _Key, class _Compare = less<_Key>,
          class _Allocator = allocator<_Key>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>,
          class = enable_if_t<!__is_allocator<_Compare>::value, void>>
 multiset(initializer_list<_Key>, _Compare = _Compare(), _Allocator = _Allocator())
   -> multiset<_Key, _Compare, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, void>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value, void>,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multiset(_InputIterator, _InputIterator, _Allocator)
   -> multiset<__iter_value_type<_InputIterator>,
          less<__iter_value_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Allocator,
          class = enable_if_t<__is_allocator<_Allocator>::value, void>>
 multiset(initializer_list<_Key>, _Allocator)

libcxx/include/stack

template <class _Alloc>
         _LIBCPP_INLINE_VISIBILITY
         stack(stack&& __s, const _Alloc& __a,
               __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
             : c(_VSTD::move(__s.c), __a) {}
 #endif // _LIBCPP_CXX03_LANG
 
 #if _LIBCPP_STD_VER >= 23
     template <class _InputIterator,
-              class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>>
+              class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>>
     _LIBCPP_HIDE_FROM_ABI
     stack(_InputIterator __first, _InputIterator __last) : c(__first, __last) {}
 
     template <class _InputIterator,
               class _Alloc,
-              class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+              class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
               class = __enable_if_t<uses_allocator<container_type, _Alloc>::value>>
     _LIBCPP_HIDE_FROM_ABI
     stack(_InputIterator __first, _InputIterator __last, const _Alloc& __alloc) : c(__first, __last, __alloc) {}
 #endif
 
     _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
     bool empty()     const      {return c.empty();}
     _LIBCPP_INLINE_VISIBILITY
template<class _Container,
          class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
          >
 stack(_Container, _Alloc)
     -> stack<typename _Container::value_type, _Container>;
 #endif
 
 #if _LIBCPP_STD_VER >= 23
 template<class _InputIterator,
-         class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>>
+         class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>>
 stack(_InputIterator, _InputIterator)
     -> stack<__iter_value_type<_InputIterator>>;
 
 template<class _InputIterator,
          class _Alloc,
-         class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = __enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = __enable_if_t<__is_allocator<_Alloc>::value>>
 stack(_InputIterator, _InputIterator, _Alloc)
     -> stack<__iter_value_type<_InputIterator>, deque<__iter_value_type<_InputIterator>, _Alloc>>;
 #endif
 
 template <class _Tp, class _Container>
 inline _LIBCPP_INLINE_VISIBILITY
 bool

libcxx/include/string

#endif
   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(
       const _Tp& __t, const allocator_type& __a)
       : __r_(__default_init_tag(), __a) {
     __self_view __sv = __t;
     __init(__sv.data(), __sv.size());
     std::__debug_db_insert_c(this);
   }
 
-  template <class _InputIterator, __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(_InputIterator __first, _InputIterator __last)
       : __r_(__default_init_tag(), __default_init_tag()) {
     __init(__first, __last);
     std::__debug_db_insert_c(this);
   }
 
-  template <class _InputIterator, __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
   basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a)
       : __r_(__default_init_tag(), __a) {
     __init(__first, __last);
     std::__debug_db_insert_c(this);
   }
 
 #ifndef _LIBCPP_CXX03_LANG
append(const _Tp& __t) {
 
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s, size_type __n);
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s);
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(size_type __n, value_type __c);
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     void __append_default_init(size_type __n);
 
-    template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
     append(_InputIterator __first, _InputIterator __last) {
         const basic_string __temp(__first, __last, __alloc());
         append(__temp.data(), __temp.size());
         return *this;
     }
 
-    template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> = 0>
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
     append(_ForwardIterator __first, _ForwardIterator __last);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
 #endif // _LIBCPP_CXX03_LANG
 
template <class _Tp,
                                 !__is_same_uncvref<_Tp, basic_string>::value,
                             int> = 0>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
     assign(const _Tp& __t, size_type __pos, size_type __n = npos);
 
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s, size_type __n);
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s);
     _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(size_type __n, value_type __c);
-    template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
     assign(_InputIterator __first, _InputIterator __last);
 
-    template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> = 0>
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
     assign(_ForwardIterator __first, _ForwardIterator __last);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
 #endif // _LIBCPP_CXX03_LANG
 
#endif // _LIBCPP_CXX03_LANG
   insert(const_iterator __pos, size_type __n, value_type __c) {
     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
                          "string::insert(iterator, n, value) called with an iterator not referring to this string");
     difference_type __p = __pos - begin();
     insert(static_cast<size_type>(__p), __n, __c);
     return begin() + __p;
   }
 
-  template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+  template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
   insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
 
-  template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> = 0>
+  template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
   insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     iterator insert(const_iterator __pos, initializer_list<value_type> __il)
                     {return insert(__pos, __il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
replace(const_iterator __i1, const_iterator __i2, const value_type* __s) {
     return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
   }
 
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c) {
     return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
   }
 
-  template <class _InputIterator, __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
   _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
         {return replace(__i1, __i2, __il.begin(), __il.end());}
 #endif // _LIBCPP_CXX03_LANG
#endif // _LIBCPP_STD_VER >= 20
     // Requires that __s is zero terminated.
     // The main reason for this function to exist is because for unstable, we
     // want to allow inlining of the copy constructor. However, we don't want
     // to call the __init() functions as those are marked as inline which may
     // result in over-aggressive inlining by the compiler, where our aim is
     // to only inline the fast path code directly in the ctor.
     _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init_copy_ctor_external(const value_type* __s, size_type __sz);
 
-    template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> = 0>
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
     inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init(_InputIterator __first, _InputIterator __last);
 
-    template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> = 0>
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
     inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init(_ForwardIterator __first, _ForwardIterator __last);
 
     _LIBCPP_CONSTEXPR_SINCE_CXX20
     void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
                    size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
     _LIBCPP_CONSTEXPR_SINCE_CXX20
     void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
                                size_type __n_copy,  size_type __n_del,

 #endif
 #undef _LIBCPP_DECLARE
 
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _CharT = __iter_value_type<_InputIterator>,
          class _Allocator = allocator<_CharT>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>
          >
 basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
   -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
 
 template<class _CharT,
          class _Traits,
          class _Allocator = allocator<_CharT>,
else
         __set_long_cap(__allocation.count);
         __set_long_size(__n);
     }
     traits_type::assign(std::__to_address(__p), __n, __c);
     traits_type::assign(__p[__n], value_type());
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> >
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 void basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
 {
     __default_init();
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
     try
     {
 #endif // _LIBCPP_HAS_NO_EXCEPTIONS
     for (; __first != __last; ++__first)
         push_back(*__first);
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
     }
     catch (...)
     {
         if (__is_long())
             __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
         throw;
     }
 #endif // _LIBCPP_HAS_NO_EXCEPTIONS
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> >
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 void
 basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
 {
     if (__libcpp_is_constant_evaluated())
         __r_.first() = __rep();
     size_type __sz = static_cast<size_type>(std::distance(__first, __last));
     if (__sz > max_size())
         __throw_length_error();
if (__libcpp_is_constant_evaluated()) {
     __str.__set_short_size(0);
     traits_type::assign(__str.__get_short_pointer()[0], value_type());
   }
 }
 
 #endif
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> >
+template<class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
 basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
 {
     const basic_string __temp(__first, __last, __alloc());
     assign(__temp.data(), __temp.size());
     return *this;
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> >
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
 basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
 {
     size_type __cap = capacity();
     size_type __n = __string_is_trivial_iterator<_ForwardIterator>::value ?
         static_cast<size_type>(std::distance(__first, __last)) : 0;
 
     if (__string_is_trivial_iterator<_ForwardIterator>::value &&
else
         __p = __get_long_pointer() + __sz;
         __set_long_size(__sz+1);
     }
     traits_type::assign(*__p, __c);
     traits_type::assign(*++__p, value_type());
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> >
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
 basic_string<_CharT, _Traits, _Allocator>::append(
     _ForwardIterator __first, _ForwardIterator __last)
 {
     size_type __sz = size();
     size_type __cap = capacity();
     size_type __n = static_cast<size_type>(std::distance(__first, __last));
     if (__n)
if (__n)
         __sz += __n;
         __set_size(__sz);
         traits_type::assign(__p[__sz], value_type());
     }
     return *this;
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, int> >
+template<class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::iterator
 basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
 {
   _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
                        "string::insert(iterator, range) called with an iterator not"
                        " referring to this string");
   const basic_string __temp(__first, __last, __alloc());
   return insert(__pos, __temp.data(), __temp.data() + __temp.size());
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, int> >
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::iterator
 basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
 {
     _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
                          "string::insert(iterator, range) called with an iterator not referring to this string");
 
     size_type __ip = static_cast<size_type>(__pos - begin());
     size_type __n = static_cast<size_type>(std::distance(__first, __last));
else
         __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
         __p = std::__to_address(__get_long_pointer());
     }
     traits_type::assign(__p + __pos, __n2, __c);
     return __null_terminate_at(__p, __sz - (__n1 - __n2));
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator, __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value, int> >
+template<class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
 basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
                                                    _InputIterator __j1, _InputIterator __j2)
 {
     const basic_string __temp(__j1, __j2, __alloc());
     return replace(__i1, __i2, __temp);
 }
 

libcxx/include/unordered_map

 #endif
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Hash = hash<__iter_key_type<_InputIterator>>,
          class _Pred = equal_to<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;
 
 template<class _Key, class _Tp, class _Hash = hash<remove_const_t<_Key>>,
          class _Pred = equal_to<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
   -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                    hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_map(_InputIterator, _InputIterator, _Allocator)
   -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                    hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _InputIterator, class _Hash, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
   -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                    _Hash, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Tp, class _Allocator,

 
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Hash = hash<__iter_key_type<_InputIterator>>,
          class _Pred = equal_to<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
                    _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;
 
 template<class _Key, class _Tp, class _Hash = hash<remove_const_t<_Key>>,
          class _Pred = equal_to<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type = 0,
                    _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
   -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                         hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multimap(_InputIterator, _InputIterator, _Allocator)
   -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                         hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _InputIterator, class _Hash, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
   -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
                         _Hash, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
 
 template<class _Key, class _Tp, class _Allocator,

libcxx/include/unordered_set

 
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Hash = hash<__iter_value_type<_InputIterator>>,
          class _Pred = equal_to<__iter_value_type<_InputIterator>>,
          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_set(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_set<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
 
 template<class _Tp, class _Hash = hash<_Tp>,
          class _Pred = equal_to<_Tp>,
          class _Allocator = allocator<_Tp>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_set<_Tp, _Hash, _Pred, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_set(_InputIterator, _InputIterator,
               typename allocator_traits<_Allocator>::size_type, _Allocator)
   -> unordered_set<__iter_value_type<_InputIterator>,
                    hash<__iter_value_type<_InputIterator>>,
                    equal_to<__iter_value_type<_InputIterator>>,
                    _Allocator>;
 
 template<class _InputIterator, class _Hash, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_set(_InputIterator, _InputIterator,
               typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
   -> unordered_set<__iter_value_type<_InputIterator>, _Hash,
                    equal_to<__iter_value_type<_InputIterator>>,
                    _Allocator>;

 
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Hash = hash<__iter_value_type<_InputIterator>>,
          class _Pred = equal_to<__iter_value_type<_InputIterator>>,
          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_multiset<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
 
 template<class _Tp, class _Hash = hash<_Tp>,
          class _Pred = equal_to<_Tp>, class _Allocator = allocator<_Tp>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<!__is_allocator<_Pred>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type = 0,
               _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
   -> unordered_multiset<_Tp, _Hash, _Pred, _Allocator>;
 
 template<class _InputIterator, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
   -> unordered_multiset<__iter_value_type<_InputIterator>,
                    hash<__iter_value_type<_InputIterator>>,
                    equal_to<__iter_value_type<_InputIterator>>,
                    _Allocator>;
 
 template<class _InputIterator, class _Hash, class _Allocator,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
 unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type,
               _Hash, _Allocator)
   -> unordered_multiset<__iter_value_type<_InputIterator>, _Hash,
                    equal_to<__iter_value_type<_InputIterator>>,
                    _Allocator>;

libcxx/include/vector

vector(size_type __n, const value_type& __x, const allocator_type& __a)
       if (__n > 0)
       {
           __vallocate(__n);
           __construct_at_end(__n, __x);
       }
     }
 
   template <class _InputIterator,
-            __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+            __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<value_type, typename iterator_traits<_InputIterator>::reference>::value,
                           int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI vector(_InputIterator __first, _InputIterator __last);
   template <class _InputIterator,
-            __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+            __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<value_type, typename iterator_traits<_InputIterator>::reference>::value,
                           int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
   vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
 
   template <
       class _ForwardIterator,
-      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+      __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<value_type, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI vector(_ForwardIterator __first, _ForwardIterator __last);
 
   template <class _ForwardIterator,
-      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+      __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<value_type, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
   vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a);
 
 #if _LIBCPP_STD_VER >= 23
   template <_ContainerCompatibleRange<_Tp> _Range>
   _LIBCPP_HIDE_FROM_ABI constexpr vector(from_range_t, _Range&& __range,
#endif
 
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
     vector(vector&& __x, const __type_identity_t<allocator_type>& __a);
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
     vector& operator=(vector&& __x)
         _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
 
   template <class _InputIterator,
-            __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+            __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<value_type, typename iterator_traits<_InputIterator>::reference>::value,
                           int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void assign(_InputIterator __first, _InputIterator __last);
   template <
       class _ForwardIterator,
-      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+      __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<value_type, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void assign(_ForwardIterator __first, _ForwardIterator __last);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<_Tp> _Range>
     _LIBCPP_HIDE_FROM_ABI
     constexpr void assign_range(_Range&& __range) {
#endif
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __position, value_type&& __x);
     template <class... _Args>
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __position, _Args&&... __args);
 
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
     iterator insert(const_iterator __position, size_type __n, const_reference __x);
 
   template <class _InputIterator,
-            __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+            __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible< value_type, typename iterator_traits<_InputIterator>::reference>::value,
                           int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator
   insert(const_iterator __position, _InputIterator __first, _InputIterator __last);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<_Tp> _Range>
     _LIBCPP_HIDE_FROM_ABI
     constexpr iterator insert_range(const_iterator __position, _Range&& __range) {
       if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
         auto __n = static_cast<size_type>(ranges::distance(__range));
         return __insert_with_size(__position, ranges::begin(__range), ranges::end(__range), __n);
 
       } else {
         return __insert_with_sentinel(__position, ranges::begin(__range), ranges::end(__range));
       }
     }
 #endif
 
   template <
       class _ForwardIterator,
-      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+      __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible< value_type, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator
   insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last);
 
 #ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
     iterator insert(const_iterator __position, initializer_list<value_type> __il)
#endif
   void __move_assign_alloc(vector&, false_type)
       _NOEXCEPT
   {}
 };
 
 #if _LIBCPP_STD_VER >= 17
 template<class _InputIterator,
          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 vector(_InputIterator, _InputIterator)
   -> vector<__iter_value_type<_InputIterator>, _Alloc>;
 
 template<class _InputIterator,
          class _Alloc,
-         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Alloc>::value>
          >
 vector(_InputIterator, _InputIterator, _Alloc)
   -> vector<__iter_value_type<_InputIterator>, _Alloc>;
 #endif
 
 #if _LIBCPP_STD_VER >= 23
 template <ranges::input_range _Range,
vector<_Tp, _Allocator>::vector(size_type __n, const value_type& __x)
     {
         __vallocate(__n);
         __construct_at_end(__n, __x);
     }
     __guard.__complete();
 }
 
 template <class _Tp, class _Allocator>
-template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<_Tp, typename iterator_traits<_InputIterator>::reference>::value,
                           int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<_Tp, _Allocator>::vector(_InputIterator __first, _InputIterator __last)
 {
   __init_with_sentinel(__first, __last);
 }
 
 template <class _Tp, class _Allocator>
-template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<_Tp, typename iterator_traits<_InputIterator>::reference>::value,
                           int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<_Tp, _Allocator>::vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a)
     : __end_cap_(nullptr, __a)
 {
   __init_with_sentinel(__first, __last);
 }
 
 template <class _Tp, class _Allocator>
-template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<_Tp, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<_Tp, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last)
 {
   size_type __n = static_cast<size_type>(std::distance(__first, __last));
   __init_with_size(__first, __last, __n);
 }
 
 template <class _Tp, class _Allocator>
-template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<_Tp, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<_Tp, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a)
     : __end_cap_(nullptr, __a)
 {
   size_type __n = static_cast<size_type>(std::distance(__first, __last));
   __init_with_size(__first, __last, __n);
vector<_Tp, _Allocator>::operator=(const vector& __x)
     {
         __copy_assign_alloc(__x);
         assign(__x.__begin_, __x.__end_);
     }
     return *this;
 }
 
 template <class _Tp, class _Allocator>
-template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<_Tp, typename iterator_traits<_InputIterator>::reference>::value,
                           int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 void
 vector<_Tp, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
 {
   __assign_with_sentinel(__first, __last);
 }
 
 template <class _Tp, class _Allocator>
 template <class _Iterator, class _Sentinel>
 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
 void vector<_Tp, _Allocator>::__assign_with_sentinel(_Iterator __first, _Sentinel __last) {
     clear();
     for (; __first != __last; ++__first)
         emplace_back(*__first);
 }
 
 template <class _Tp, class _Allocator>
-template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<_Tp, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 void
 vector<_Tp, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
 {
   __assign_with_size(__first, __last, std::distance(__first, __last));
 }
 
if (__n > 0)
             __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), __p - this->__begin_, __a);
             __v.__construct_at_end(__n, __x);
             __p = __swap_out_circular_buffer(__v, __p);
         }
     }
     return __make_iter(__p);
 }
 template <class _Tp, class _Allocator>
-template <class _InputIterator, __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value &&
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value &&
                               is_constructible<_Tp, typename iterator_traits<_InputIterator>::reference>::value,
                           int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 typename vector<_Tp, _Allocator>::iterator
 vector<_Tp, _Allocator>::insert(const_iterator __position, _InputIterator __first, _InputIterator __last)
 {
   return __insert_with_sentinel(__position, __first, __last);
 }
 
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
     }
     __p = std::rotate(__p, __old_last, this->__end_);
     insert(__make_iter(__p), std::make_move_iterator(__v.begin()),
                              std::make_move_iterator(__v.end()));
     return begin() + __off;
 }
 
 template <class _Tp, class _Allocator>
-template <class _ForwardIterator, __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value &&
                         is_constructible<_Tp, typename iterator_traits<_ForwardIterator>::reference>::value,
                     int> >
 _LIBCPP_CONSTEXPR_SINCE_CXX20 typename vector<_Tp, _Allocator>::iterator
 vector<_Tp, _Allocator>::insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last)
 {
   return __insert_with_size(__position, __first, __last, std::distance(__first, __last));
 }
 
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~vector() { __destroy_vector(*this)(); }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit vector(size_type __n);
 #if _LIBCPP_STD_VER >= 14
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit vector(size_type __n, const allocator_type& __a);
 #endif
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(size_type __n, const value_type& __v);
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(size_type __n, const value_type& __v, const allocator_type& __a);
     template <class _InputIterator>
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(_InputIterator __first, _InputIterator __last,
-               typename enable_if<__is_exactly_cpp17_input_iterator<_InputIterator>::value>::type* = 0);
+               typename enable_if<__has_exactly_input_iterator_category<_InputIterator>::value>::type* = 0);
     template <class _InputIterator>
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
-               typename enable_if<__is_exactly_cpp17_input_iterator<_InputIterator>::value>::type* = 0);
+               typename enable_if<__has_exactly_input_iterator_category<_InputIterator>::value>::type* = 0);
     template <class _ForwardIterator>
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(_ForwardIterator __first, _ForwardIterator __last,
-               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type* = 0);
+               typename enable_if<__has_forward_iterator_category<_ForwardIterator>::value>::type* = 0);
     template <class _ForwardIterator>
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
-               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type* = 0);
+               typename enable_if<__has_forward_iterator_category<_ForwardIterator>::value>::type* = 0);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<bool> _Range>
     _LIBCPP_HIDE_FROM_ABI constexpr
     vector(from_range_t, _Range&& __range, const allocator_type& __a = allocator_type())
     : __begin_(nullptr),
       __size_(0),
       __cap_alloc_(0, static_cast<__storage_allocator>(__a)) {
#else
         _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
 #endif
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 vector(vector&& __v, const __type_identity_t<allocator_type>& __a);
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
     vector& operator=(vector&& __v)
         _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
 
     template <class _InputIterator>
-        typename enable_if <__is_exactly_cpp17_input_iterator<_InputIterator>::value,
+        typename enable_if <__has_exactly_input_iterator_category<_InputIterator>::value,
            void
         >::type
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 assign(_InputIterator __first, _InputIterator __last);
     template <class _ForwardIterator>
         typename enable_if
         <
-            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            __has_forward_iterator_category<_ForwardIterator>::value,
            void
         >::type
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 assign(_ForwardIterator __first, _ForwardIterator __last);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<bool> _Range>
     _LIBCPP_HIDE_FROM_ABI
     constexpr void assign_range(_Range&& __range) {
#if _LIBCPP_STD_VER >= 14
     template <class... _Args>
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator emplace(const_iterator __position, _Args&&... __args)
         { return insert ( __position, value_type ( std::forward<_Args>(__args)... )); }
 #endif
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator insert(const_iterator __position, const value_type& __x);
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator insert(const_iterator __position, size_type __n, const value_type& __x);
     template <class _InputIterator>
-        typename enable_if <__is_exactly_cpp17_input_iterator<_InputIterator>::value,
+        typename enable_if <__has_exactly_input_iterator_category<_InputIterator>::value,
             iterator
         >::type
         _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 insert(const_iterator __position, _InputIterator __first, _InputIterator __last);
     template <class _ForwardIterator>
         typename enable_if
         <
-            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            __has_forward_iterator_category<_ForwardIterator>::value,
             iterator
         >::type
         _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last);
 
 #if _LIBCPP_STD_VER >= 23
     template <_ContainerCompatibleRange<bool> _Range>
     _LIBCPP_HIDE_FROM_ABI
     constexpr iterator insert_range(const_iterator __position, _Range&& __range) {
if (__n > 0)
         __construct_at_end(__n, __x);
     }
 }
 
 template <class _Allocator>
 template <class _InputIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<bool, _Allocator>::vector(_InputIterator __first, _InputIterator __last,
-       typename enable_if<__is_exactly_cpp17_input_iterator<_InputIterator>::value>::type*)
+       typename enable_if<__has_exactly_input_iterator_category<_InputIterator>::value>::type*)
     : __begin_(nullptr),
       __size_(0),
       __cap_alloc_(0, __default_init_tag())
 {
   __init_with_sentinel(__first, __last);
 }
 
 template <class _Allocator>
 template <class _InputIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<bool, _Allocator>::vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
-       typename enable_if<__is_exactly_cpp17_input_iterator<_InputIterator>::value>::type*)
+       typename enable_if<__has_exactly_input_iterator_category<_InputIterator>::value>::type*)
     : __begin_(nullptr),
       __size_(0),
       __cap_alloc_(0, static_cast<__storage_allocator>(__a))
 {
   __init_with_sentinel(__first, __last);
 }
 
 template <class _Allocator>
 template <class _ForwardIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<bool, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last,
-                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type*)
+                                typename enable_if<__has_forward_iterator_category<_ForwardIterator>::value>::type*)
     : __begin_(nullptr),
       __size_(0),
       __cap_alloc_(0, __default_init_tag())
 {
   auto __n = static_cast<size_type>(std::distance(__first, __last));
   __init_with_size(__first, __last, __n);
 }
 
 template <class _Allocator>
 template <class _ForwardIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 vector<bool, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
-                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type*)
+                                typename enable_if<__has_forward_iterator_category<_ForwardIterator>::value>::type*)
     : __begin_(nullptr),
       __size_(0),
       __cap_alloc_(0, static_cast<__storage_allocator>(__a))
 {
   auto __n = static_cast<size_type>(std::distance(__first, __last));
   __init_with_size(__first, __last, __n);
 }
 
if (__n > 0)
         }
         std::fill_n(begin(), __n, __x);
     }
     std::__debug_db_invalidate_all(this);
 }
 
 template <class _Allocator>
 template <class _InputIterator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20 typename enable_if <__is_exactly_cpp17_input_iterator<_InputIterator>::value,
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename enable_if <__has_exactly_input_iterator_category<_InputIterator>::value,
    void
 >::type
 vector<bool, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
 {
   __assign_with_sentinel(__first, __last);
 }
 
 template <class _Allocator>
 template <class _Iterator, class _Sentinel>
 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
 void vector<bool, _Allocator>::__assign_with_sentinel(_Iterator __first, _Sentinel __last) {
     clear();
     for (; __first != __last; ++__first)
         push_back(*__first);
 }
 
 template <class _Allocator>
 template <class _ForwardIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename enable_if
 <
-    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    __has_forward_iterator_category<_ForwardIterator>::value,
    void
 >::type
 vector<bool, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
 {
   __assign_with_size(__first, __last, std::distance(__first, __last));
 }
 
 template <class _Allocator>
else
         swap(__v);
     }
     std::fill_n(__r, __n, __x);
     return __r;
 }
 
 template <class _Allocator>
 template <class _InputIterator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20 typename enable_if <__is_exactly_cpp17_input_iterator<_InputIterator>::value,
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename enable_if <__has_exactly_input_iterator_category<_InputIterator>::value,
     typename vector<bool, _Allocator>::iterator
 >::type
 vector<bool, _Allocator>::insert(const_iterator __position, _InputIterator __first, _InputIterator __last)
 {
   return __insert_with_sentinel(__position, __first, __last);
 }
 
 template <class _Allocator>
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
     return begin() + __off;
 }
 
 template <class _Allocator>
 template <class _ForwardIterator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename enable_if
 <
-    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    __has_forward_iterator_category<_ForwardIterator>::value,
     typename vector<bool, _Allocator>::iterator
 >::type
 vector<bool, _Allocator>::insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last)
 {
   return __insert_with_size(__position, __first, __last, std::distance(__first, __last));
 }
 
 template <class _Allocator>

libcxx/test/libcxx/iterators/contiguous_iterators.pass.cpp

public:
     friend bool operator<=(const Self&, const Self&);
     friend bool operator>=(const Self&, const Self&);
 };
 #endif
 
 struct fake_deque_iterator : std::deque<int>::iterator {
     using element_type = int;
 };
-static_assert(std::__is_cpp17_random_access_iterator<fake_deque_iterator>::value, "");
+static_assert(std::__has_random_access_iterator_category<fake_deque_iterator>::value, "");
 static_assert(!std::__is_cpp17_contiguous_iterator<fake_deque_iterator>::value, "");
 
 #if TEST_STD_VER >= 20
 struct fake2_deque_iterator : std::deque<int>::iterator {
     using iterator_concept = std::contiguous_iterator_tag;
     using element_type = int;
 };
-static_assert(std::__is_cpp17_random_access_iterator<fake2_deque_iterator>::value, "");
+static_assert(std::__has_random_access_iterator_category<fake2_deque_iterator>::value, "");
 static_assert(std::__is_cpp17_contiguous_iterator<fake2_deque_iterator>::value, "");
 #endif
 
 int main(int, char**)
 {
 //  basic tests
     static_assert(( std::__is_cpp17_contiguous_iterator<char *>::value), "");
     static_assert(( std::__is_cpp17_contiguous_iterator<const char *>::value), "");

libcxx/test/std/containers/views/views.span/span.iterators/iterator_concept_conformance.compile.pass.cpp

 #include <iterator>
 #include "test_macros.h"
 
 using iterator = std::span<int>::iterator;
 using reverse_iterator = std::span<int>::reverse_iterator;
 using value_type = int;
 
 static_assert(std::contiguous_iterator<iterator>);
-LIBCPP_STATIC_ASSERT(std::__is_cpp17_random_access_iterator<iterator>::value);
+LIBCPP_STATIC_ASSERT(std::__has_random_access_iterator_category<iterator>::value);
 static_assert(std::indirectly_writable<iterator, value_type>);
 static_assert(std::sentinel_for<iterator, iterator>);
 static_assert(!std::sentinel_for<iterator, reverse_iterator>);
 static_assert(std::sized_sentinel_for<iterator, iterator>);
 static_assert(!std::sized_sentinel_for<iterator, reverse_iterator>);
 static_assert(std::indirectly_movable<iterator, int*>);
 static_assert(std::indirectly_movable_storable<iterator, int*>);
 static_assert(std::indirectly_copyable<iterator, int*>);
 static_assert(std::indirectly_copyable_storable<iterator, int*>);
 static_assert(std::indirectly_swappable<iterator, iterator>);

libcxx/test/std/strings/string.view/string.view.iterators/iterator_concept_conformance.compile.pass.cpp

 #include "test_macros.h"
 
 using iterator = std::string_view::iterator;
 using const_iterator = std::string_view::const_iterator;
 using reverse_iterator = std::string_view::reverse_iterator;
 using const_reverse_iterator = std::string_view::const_reverse_iterator;
 
 static_assert(std::contiguous_iterator<iterator>);
-LIBCPP_STATIC_ASSERT(std::__is_cpp17_random_access_iterator<iterator>::value);
+LIBCPP_STATIC_ASSERT(std::__has_random_access_iterator_category<iterator>::value);
 static_assert(!std::indirectly_writable<iterator, char>);
 static_assert(std::sentinel_for<iterator, iterator>);
 static_assert(std::sentinel_for<iterator, const_iterator>);
 static_assert(!std::sentinel_for<iterator, reverse_iterator>);
 static_assert(!std::sentinel_for<iterator, const_reverse_iterator>);
 static_assert(std::sized_sentinel_for<iterator, iterator>);
 static_assert(std::sized_sentinel_for<iterator, const_iterator>);
 static_assert(!std::sized_sentinel_for<iterator, reverse_iterator>);
 static_assert(!std::sized_sentinel_for<iterator, const_reverse_iterator>);
 static_assert(std::indirectly_movable<iterator, char*>);
 static_assert(std::indirectly_movable_storable<iterator, char*>);
 static_assert(std::indirectly_copyable<iterator, char*>);
 static_assert(std::indirectly_copyable_storable<iterator, char*>);
 static_assert(!std::indirectly_swappable<iterator, iterator>);
 
 static_assert(std::contiguous_iterator<const_iterator>);
-LIBCPP_STATIC_ASSERT(std::__is_cpp17_random_access_iterator<const_iterator>::value);
+LIBCPP_STATIC_ASSERT(std::__has_random_access_iterator_category<const_iterator>::value);
 static_assert(!std::indirectly_writable<const_iterator, char>);
 static_assert(std::sentinel_for<const_iterator, iterator>);
 static_assert(std::sentinel_for<const_iterator, const_iterator>);
 static_assert(!std::sentinel_for<const_iterator, reverse_iterator>);
 static_assert(!std::sentinel_for<const_iterator, const_reverse_iterator>);
 static_assert(std::sized_sentinel_for<const_iterator, iterator>);
 static_assert(std::sized_sentinel_for<const_iterator, const_iterator>);
 static_assert(!std::sized_sentinel_for<const_iterator, reverse_iterator>);
 static_assert(!std::sized_sentinel_for<const_iterator, const_reverse_iterator>);
 static_assert(!std::indirectly_swappable<const_iterator, const_iterator>);