[libc++][NFC] Prefer type aliases over structs

[philnik]

• Try to fix CI

[philnik]

• Try to fix CI

libcxx/include/__algorithm/binary_search.h

 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _ForwardIterator, class _Tp, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp)
 {
-    using _Comp_ref = typename __comp_ref_type<_Compare>::type;
-    __first = std::lower_bound<_ForwardIterator, _Tp, _Comp_ref>(__first, __last, __value, __comp);
+    __first = std::lower_bound<_ForwardIterator, _Tp, __comp_ref_type<_Compare> >(__first, __last, __value, __comp);
     return __first != __last && !__comp(__value, *__first);
 }
 
 template <class _ForwardIterator, class _Tp>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
 {
     return std::binary_search(__first, __last, __value,
                               __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_BINARY_SEARCH_H

libcxx/include/__algorithm/comp_ref_type.h

struct __debug_less
     }
 
     template <class _LHS, class _RHS>
     _LIBCPP_CONSTEXPR_SINCE_CXX14
     inline _LIBCPP_INLINE_VISIBILITY
     void __do_compare_assert(long, _LHS &, _RHS &) {}
 };
 
-template <class _Comp>
-struct __comp_ref_type {
-  // Pass the comparator by lvalue reference. Or in debug mode, using a
-  // debugging wrapper that stores a reference.
 #ifdef _LIBCPP_ENABLE_DEBUG_MODE
-  typedef __debug_less<_Comp> type;
+template <class _Comp>
+using __comp_ref_type = __debug_less<_Comp>;
 #else
-  typedef _Comp& type;
+template <class _Comp>
+using __comp_ref_type = _Comp&;
 #endif
-};
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_COMP_REF_TYPE_H

libcxx/include/__algorithm/equal_range.h

 
 template <class _ForwardIterator, class _Tp, class _Compare>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
   static_assert(__is_callable<_Compare, decltype(*__first), const _Tp&>::value,
                 "The comparator has to be callable");
   static_assert(is_copy_constructible<_ForwardIterator>::value,
                 "Iterator has to be copy constructible");
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
   return std::__equal_range<_ClassicAlgPolicy>(
-      std::move(__first), std::move(__last), __value, static_cast<_Comp_ref>(__comp), std::__identity());
+      std::move(__first),
+      std::move(__last),
+      __value,
+      static_cast<__comp_ref_type<_Compare> >(__comp),
+      std::__identity());
 }
 
 template <class _ForwardIterator, class _Tp>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   return std::equal_range(
       std::move(__first),
       std::move(__last),
       __value,
       __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H

libcxx/include/__algorithm/includes.h

_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool includes(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _Compare __comp) {
   static_assert(__is_callable<_Compare, decltype(*__first1), decltype(*__first2)>::value,
       "Comparator has to be callable");
 
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
   return std::__includes(
-      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
-      static_cast<_Comp_ref>(__comp), __identity(), __identity());
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__last2),
+      static_cast<__comp_ref_type<_Compare> >(__comp),
+      __identity(),
+      __identity());
 }
 
 template <class _InputIterator1, class _InputIterator2>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
   return std::includes(
       std::move(__first1),
       std::move(__last1),

libcxx/include/__algorithm/inplace_merge.h

_LIBCPP_SUPPRESS_DEPRECATED_POP
     unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
     return std::__inplace_merge<_AlgPolicy>(
         std::move(__first), std::move(__middle), std::move(__last), __comp, __len1, __len2, __buf.first, __buf.second);
 }
 
 template <class _BidirectionalIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI void inplace_merge(
     _BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Compare __comp) {
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
   std::__inplace_merge<_ClassicAlgPolicy>(
-      std::move(__first), std::move(__middle), std::move(__last), static_cast<_Comp_ref>(__comp));
+      std::move(__first), std::move(__middle), std::move(__last), static_cast<__comp_ref_type<_Compare>>(__comp));
 }
 
 template <class _BidirectionalIterator>
 inline _LIBCPP_HIDE_FROM_ABI
 void
 inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
 {
     std::inplace_merge(std::move(__first), std::move(__middle), std::move(__last),
                         __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___ALGORITHM_INPLACE_MERGE_H

libcxx/include/__algorithm/is_heap.h

 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _RandomAccessIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return std::__is_heap_until(__first, __last, static_cast<_Comp_ref>(__comp)) == __last;
+    return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp)) == __last;
 }
 
 template<class _RandomAccessIterator>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
 {
     return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_IS_HEAP_H

libcxx/include/__algorithm/is_heap_until.h

__is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp)
     }
     return __last;
 }
 
 template <class _RandomAccessIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return std::__is_heap_until(__first, __last, static_cast<_Comp_ref>(__comp));
+    return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
 }
 
 template<class _RandomAccessIterator>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
 {
     return _VSTD::__is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H

libcxx/include/__algorithm/is_sorted.h

 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _ForwardIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return _VSTD::__is_sorted_until<_Comp_ref>(__first, __last, __comp) == __last;
+    return _VSTD::__is_sorted_until<__comp_ref_type<_Compare> >(__first, __last, __comp) == __last;
 }
 
 template<class _ForwardIterator>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 is_sorted(_ForwardIterator __first, _ForwardIterator __last)
 {
     return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_IS_SORTED_H

libcxx/include/__algorithm/is_sorted_until.h

__is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
     }
     return __last;
 }
 
 template <class _ForwardIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return _VSTD::__is_sorted_until<_Comp_ref>(__first, __last, __comp);
+    return _VSTD::__is_sorted_until<__comp_ref_type<_Compare> >(__first, __last, __comp);
 }
 
 template<class _ForwardIterator>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
 {
     return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H

libcxx/include/__algorithm/lexicographical_compare.h

 
 template <class _InputIterator1, class _InputIterator2, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
                         _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return _VSTD::__lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
+    return _VSTD::__lexicographical_compare<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __comp);
 }
 
 template <class _InputIterator1, class _InputIterator2>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
                         _InputIterator2 __first2, _InputIterator2 __last2)

libcxx/include/__algorithm/make_heap.h

 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 void __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
-  using _CompRef = typename __comp_ref_type<_Compare>::type;
-  _CompRef __comp_ref = __comp;
+  __comp_ref_type<_Compare> __comp_ref = __comp;
 
   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
   difference_type __n = __last - __first;
   if (__n > 1) {
     // start from the first parent, there is no need to consider children
     for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start) {
         std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
     }

libcxx/include/__algorithm/max.h

 #ifndef _LIBCPP_CXX03_LANG
 
 template<class _Tp, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
 _Tp
 max(initializer_list<_Tp> __t, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return *_VSTD::__max_element<_Comp_ref>(__t.begin(), __t.end(), __comp);
+    return *_VSTD::__max_element<__comp_ref_type<_Compare> >(__t.begin(), __t.end(), __comp);
 }
 
 template<class _Tp>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
 _Tp
 max(initializer_list<_Tp> __t)
 {

libcxx/include/__algorithm/max_element.h

__max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
     }
     return __first;
 }
 
 template <class _ForwardIterator, class _Compare>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
 max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return _VSTD::__max_element<_Comp_ref>(__first, __last, __comp);
+    return _VSTD::__max_element<__comp_ref_type<_Compare> >(__first, __last, __comp);
 }
 
 
 template <class _ForwardIterator>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
 max_element(_ForwardIterator __first, _ForwardIterator __last)
 {
     return _VSTD::max_element(__first, __last,
               __less<typename iterator_traits<_ForwardIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_MAX_ELEMENT_H

libcxx/include/__algorithm/merge.h

 }
 
 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 _OutputIterator
 merge(_InputIterator1 __first1, _InputIterator1 __last1,
       _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+    return _VSTD::__merge<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __result, __comp);
 }
 
 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 _OutputIterator
 merge(_InputIterator1 __first1, _InputIterator1 __last1,
       _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
 {
     typedef typename iterator_traits<_InputIterator1>::value_type __v1;
     typedef typename iterator_traits<_InputIterator2>::value_type __v2;
     return _VSTD::merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_MERGE_H

libcxx/include/__algorithm/min.h

 #ifndef _LIBCPP_CXX03_LANG
 
 template<class _Tp, class _Compare>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
 _Tp
 min(initializer_list<_Tp> __t, _Compare __comp)
 {
-    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-    return *_VSTD::__min_element<_Comp_ref>(__t.begin(), __t.end(), __comp);
+    return *_VSTD::__min_element<__comp_ref_type<_Compare> >(__t.begin(), __t.end(), __comp);
 }
 
 template<class _Tp>
 _LIBCPP_NODISCARD_EXT inline
 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
 _Tp
 min(initializer_list<_Tp> __t)
 {

libcxx/include/__algorithm/min_element.h

 _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,
       "std::min_element requires a ForwardIterator");
   static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
               "The comparator has to be callable");
 
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__min_element<_Comp_ref>(std::move(__first), std::move(__last), __comp);
+  return std::__min_element<__comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp);
 }
 
 template <class _ForwardIterator>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
 min_element(_ForwardIterator __first, _ForwardIterator __last)
 {
     return _VSTD::min_element(__first, __last,
               __less<typename iterator_traits<_ForwardIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_MIN_ELEMENT_H

libcxx/include/__algorithm/next_permutation.h

__next_permutation(_BidirectionalIterator __first, _Sentinel __last, _Compare&& __comp)
     }
 }
 
 template <class _BidirectionalIterator, class _Compare>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
 {
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
   return std::__next_permutation<_ClassicAlgPolicy>(
-      std::move(__first), std::move(__last), static_cast<_Comp_ref>(__comp)).second;
+      std::move(__first), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp)).second;
 }
 
 template <class _BidirectionalIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
 {
     return _VSTD::next_permutation(__first, __last,
                                   __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H

libcxx/include/__algorithm/nth_element.h

 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 void __nth_element_impl(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last,
                         _Compare& __comp) {
   if (__nth == __last)
     return;
 
   std::__debug_randomize_range<_AlgPolicy>(__first, __last);
 
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
-  std::__nth_element<_AlgPolicy, _Comp_ref>(__first, __nth, __last, __comp);
+  std::__nth_element<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __nth, __last, __comp);
 
   std::__debug_randomize_range<_AlgPolicy>(__first, __nth);
   if (__nth != __last) {
     std::__debug_randomize_range<_AlgPolicy>(++__nth, __last);
   }
 }
 
 template <class _RandomAccessIterator, class _Compare>

libcxx/include/__algorithm/partial_sort.h

 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 _RandomAccessIterator __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _Sentinel __last,
                                      _Compare& __comp) {
   if (__first == __middle)
       return _IterOps<_AlgPolicy>::next(__middle, __last);
 
   std::__debug_randomize_range<_AlgPolicy>(__first, __last);
 
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
-  auto __last_iter = std::__partial_sort_impl<_AlgPolicy>(__first, __middle, __last, static_cast<_Comp_ref>(__comp));
+  auto __last_iter =
+      std::__partial_sort_impl<_AlgPolicy>(__first, __middle, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
 
   std::__debug_randomize_range<_AlgPolicy>(__middle, __last);
 
   return __last_iter;
 }
 
 template <class _RandomAccessIterator, class _Compare>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20

libcxx/include/__algorithm/partial_sort_copy.h

 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 _RandomAccessIterator
 partial_sort_copy(_InputIterator __first, _InputIterator __last,
                   _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
 {
   static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__result_first)>::value,
                 "Comparator has to be callable");
 
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
   auto __result = std::__partial_sort_copy<_ClassicAlgPolicy>(__first, __last, __result_first, __result_last,
-      static_cast<_Comp_ref>(__comp), __identity(), __identity());
+      static_cast<__comp_ref_type<_Compare> >(__comp), __identity(), __identity());
   return __result.second;
 }
 
 template <class _InputIterator, class _RandomAccessIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 _RandomAccessIterator
 partial_sort_copy(_InputIterator __first, _InputIterator __last,
                   _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
 {
     return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
                                    __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H

libcxx/include/__algorithm/pop_heap.h

 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 void __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp,
     typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
   _LIBCPP_ASSERT(__len > 0, "The heap given to pop_heap must be non-empty");
 
-  using _CompRef = typename __comp_ref_type<_Compare>::type;
-  _CompRef __comp_ref = __comp;
+  __comp_ref_type<_Compare> __comp_ref = __comp;
 
   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
   if (__len > 1) {
     value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first);  // create a hole at __first
     _RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len);
     --__last;
 
     if (__hole == __last) {

libcxx/include/__algorithm/prev_permutation.h

__prev_permutation(_BidirectionalIterator __first, _Sentinel __last, _Compare&& __comp)
     }
 }
 
 template <class _BidirectionalIterator, class _Compare>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
 {
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
   return std::__prev_permutation<_ClassicAlgPolicy>(
-      std::move(__first), std::move(__last), static_cast<_Comp_ref>(__comp)).second;
+      std::move(__first), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp)).second;
 }
 
 template <class _BidirectionalIterator>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
 bool
 prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
 {
     return _VSTD::prev_permutation(__first, __last,
                                   __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_PREV_PERMUTATION_H

libcxx/include/__algorithm/push_heap.h

if (__comp(*__ptr, *--__last)) {
       *__last = std::move(__t);
     }
   }
 }
 
 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
-  using _CompRef = typename __comp_ref_type<_Compare>::type;
   typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
-  std::__sift_up<_AlgPolicy, _CompRef>(std::move(__first), std::move(__last), __comp, __len);
+  std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
 }
 
 template <class _RandomAccessIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
   static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
   static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
 

libcxx/include/__algorithm/set_difference.h

 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_difference(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _OutputIterator __result,
     _Compare __comp) {
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp).second;
+  return std::__set_difference<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __result, __comp)
+      .second;
 }
 
 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_difference(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,

libcxx/include/__algorithm/set_intersection.h

 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_intersection(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _OutputIterator __result,
     _Compare __comp) {
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_intersection<_ClassicAlgPolicy, _Comp_ref>(
+  return std::__set_intersection<_ClassicAlgPolicy, __comp_ref_type<_Compare> >(
              std::move(__first1),
              std::move(__last1),
              std::move(__first2),
              std::move(__last2),
              std::move(__result),
              __comp)
       .__out_;
 }

libcxx/include/__algorithm/set_symmetric_difference.h

 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_symmetric_difference(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _OutputIterator __result,
     _Compare __comp) {
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_symmetric_difference<_Comp_ref>(
+  return std::__set_symmetric_difference<__comp_ref_type<_Compare> >(
              std::move(__first1),
              std::move(__last1),
              std::move(__first2),
              std::move(__last2),
              std::move(__result),
              __comp)
       .__out_;
 }

libcxx/include/__algorithm/set_union.h

 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator set_union(
     _InputIterator1 __first1,
     _InputIterator1 __last1,
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _OutputIterator __result,
     _Compare __comp) {
-  typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_union<_Comp_ref>(
+  return std::__set_union<__comp_ref_type<_Compare> >(
              std::move(__first1),
              std::move(__last1),
              std::move(__first2),
              std::move(__last2),
              std::move(__result),
              __comp)
       .__out_;
 }

libcxx/include/__algorithm/sort.h

 
 extern template _LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&);
 
 template <class _AlgPolicy, class _RandomAccessIterator, class _Comp>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 void __sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Comp& __comp) {
   std::__debug_randomize_range<_AlgPolicy>(__first, __last);
 
-  using _Comp_ref = typename __comp_ref_type<_Comp>::type;
+  using _Comp_ref = __comp_ref_type<_Comp>;
   if (__libcpp_is_constant_evaluated()) {
     std::__partial_sort<_AlgPolicy>(__first, __last, __last, __comp);
 
   } else {
     using _WrappedComp = typename _WrapAlgPolicy<_AlgPolicy, _Comp_ref>::type;
     _Comp_ref __comp_ref(__comp);
     _WrappedComp __wrapped_comp(__comp_ref);
     std::__sort<_WrappedComp>(std::__unwrap_iter(__first), std::__unwrap_iter(__last), __wrapped_comp);

libcxx/include/__algorithm/sort_heap.h

 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 void __sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
-  using _CompRef = typename __comp_ref_type<_Compare>::type;
-  _CompRef __comp_ref = __comp;
+  __comp_ref_type<_Compare> __comp_ref = __comp;
 
   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
   for (difference_type __n = __last - __first; __n > 1; --__last, (void) --__n)
     std::__pop_heap<_AlgPolicy>(__first, __last, __comp_ref, __n);
 }
 
 template <class _RandomAccessIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20

libcxx/include/__algorithm/stable_sort.h

void __stable_sort_impl(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
   if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value)) {
 // TODO: Remove the use of std::get_temporary_buffer
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
       __buf = std::get_temporary_buffer<value_type>(__len);
 _LIBCPP_SUPPRESS_DEPRECATED_POP
       __h.reset(__buf.first);
   }
 
-  using _Comp_ref = typename __comp_ref_type<_Compare>::type;
-  std::__stable_sort<_AlgPolicy, _Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
+  std::__stable_sort<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __last, __comp, __len, __buf.first, __buf.second);
 }
 
 template <class _RandomAccessIterator, class _Compare>
 inline _LIBCPP_HIDE_FROM_ABI
 void stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
   std::__stable_sort_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
 }
 

libcxx/include/__algorithm/unique_copy.h

if (__first != __last) {
     ++__result;
   }
   return pair<_InputIterator, _InputAndOutputIterator>(std::move(__first), std::move(__result));
 }
 
 template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred) {
-  using __algo_tag = typename conditional<
+  using __algo_tag = __conditional_t<
       is_base_of<forward_iterator_tag, typename iterator_traits<_InputIterator>::iterator_category>::value,
       __unique_copy_tags::__reread_from_input_tag,
-      typename conditional<
+      __conditional_t<
           is_base_of<forward_iterator_tag, typename iterator_traits<_OutputIterator>::iterator_category>::value &&
               is_same< typename iterator_traits<_InputIterator>::value_type,
                        typename iterator_traits<_OutputIterator>::value_type>::value,
           __unique_copy_tags::__reread_from_output_tag,
-          __unique_copy_tags::__read_from_tmp_value_tag>::type >::type;
+          __unique_copy_tags::__read_from_tmp_value_tag> >;
   return std::__unique_copy<_ClassicAlgPolicy>(
              std::move(__first), std::move(__last), std::move(__result), __pred, __algo_tag())
       .second;
 }
 
 template <class _InputIterator, class _OutputIterator>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
   typedef typename iterator_traits<_InputIterator>::value_type __v;
   return std::unique_copy(std::move(__first), std::move(__last), std::move(__result), __equal_to<__v>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_UNIQUE_COPY_H

libcxx/include/__bit_reference

template <class _Cp, bool _IsConst,
           typename _Cp::__storage_type>
 class __bit_iterator
 {
 public:
     typedef typename _Cp::difference_type                                                          difference_type;
     typedef bool                                                                                  value_type;
     typedef __bit_iterator                                                                        pointer;
 #ifndef _LIBCPP_ABI_BITSET_VECTOR_BOOL_CONST_SUBSCRIPT_RETURN_BOOL
-    typedef typename conditional<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >::type reference;
+    typedef __conditional_t<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> > reference;
 #else
-    using reference = typename conditional<_IsConst, bool, __bit_reference<_Cp> >::type;
+    using reference = __conditional_t<_IsConst, bool, __bit_reference<_Cp> >;
 #endif
     typedef random_access_iterator_tag                                                            iterator_category;
 
 private:
     typedef typename _Cp::__storage_type                                           __storage_type;
-    typedef typename conditional<_IsConst, typename _Cp::__const_storage_pointer,
-                                           typename _Cp::__storage_pointer>::type  __storage_pointer;
+    typedef __conditional_t<_IsConst, typename _Cp::__const_storage_pointer, typename _Cp::__storage_pointer>
+        __storage_pointer;
     static const unsigned __bits_per_word = _Cp::__bits_per_word;
 
     __storage_pointer __seg_;
     unsigned          __ctz_;
 
 public:
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator() _NOEXCEPT
 #if _LIBCPP_STD_VER > 11
#endif
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
     __bit_iterator& operator=(const _If<_IsConst, struct __private_nat, __bit_iterator>& __it) {
         __seg_ = __it.__seg_;
         __ctz_ = __it.__ctz_;
         return *this;
     }
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator*() const _NOEXCEPT {
-        return typename conditional<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >
-                ::type(__seg_, __storage_type(1) << __ctz_);
+        return __conditional_t<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >(
+            __seg_, __storage_type(1) << __ctz_);
     }
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator& operator++()
     {
         if (__ctz_ != __bits_per_word-1)
             ++__ctz_;
         else
         {

libcxx/include/__coroutine/coroutine_traits.h

 //    using promise_type = typename R::promise_type;
 //
 // Otherwise, coroutine_traits<R, ArgTypes...> has no members.
 template <class _Tp, class = void>
 struct __coroutine_traits_sfinae {};
 
 template <class _Tp>
 struct __coroutine_traits_sfinae<
-    _Tp, typename __void_t<typename _Tp::promise_type>::type>
+    _Tp, __void_t<typename _Tp::promise_type> >
 {
   using promise_type = typename _Tp::promise_type;
 };
 
 template <class _Ret, class... _Args>
 struct coroutine_traits
     : public __coroutine_traits_sfinae<_Ret>
 {
 };
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // __LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CXX20_COROUTINES)
 
 #endif // _LIBCPP___COROUTINE_COROUTINE_TRAITS_H

libcxx/include/__functional/function.h

#endif
         };
         return &__policy_;
     }
 };
 
 // Used to choose between perfect forwarding or pass-by-value. Pass-by-value is
 // faster for types that can be passed in registers.
 template <typename _Tp>
-using __fast_forward =
-    typename conditional<is_scalar<_Tp>::value, _Tp, _Tp&&>::type;
+using __fast_forward = __conditional_t<is_scalar<_Tp>::value, _Tp, _Tp&&>;
 
 // __policy_invoker calls an instance of __alloc_func held in __policy_storage.
 
 template <class _Fp> struct __policy_invoker;
 
 template <class _Rp, class... _ArgTypes>
 struct __policy_invoker<_Rp(_ArgTypes...)>
 {

libcxx/include/__functional/invoke.h

struct __invokable_r
   static decltype(std::__invoke(declval<_XFp>(), declval<_XArgs>()...)) __try_call(int);
   template <class _XFp, class ..._XArgs>
   static __nat __try_call(...);
 
   // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
   // or incomplete array types as required by the standard.
   using _Result = decltype(__try_call<_Fp, _Args...>(0));
 
-  using type = typename conditional<
+  using type = __conditional_t<
       _IsNotSame<_Result, __nat>::value,
-      typename conditional< is_void<_Ret>::value, true_type, __is_core_convertible<_Result, _Ret> >::type,
-      false_type >::type;
+      __conditional_t<is_void<_Ret>::value, true_type, __is_core_convertible<_Result, _Ret> >,
+      false_type>;
   static const bool value = type::value;
 };
 template <class _Fp, class ..._Args>
 using __invokable = __invokable_r<void, _Fp, _Args...>;
 
 template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
 struct __nothrow_invokable_r_imp {
   static const bool value = false;

libcxx/include/__functional/is_transparent.h

 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER > 11
 
 template <class _Tp, class, class = void>
 struct __is_transparent : false_type {};
 
 template <class _Tp, class _Up>
-struct __is_transparent<_Tp, _Up,
-                        typename __void_t<typename _Tp::is_transparent>::type>
+struct __is_transparent<_Tp, _Up, __void_t<typename _Tp::is_transparent> >
    : true_type {};
 
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT

libcxx/include/__hash_table

struct __hash_node_base
     typedef typename pointer_traits<_NodePtr>::element_type __node_type;
     typedef __hash_node_base __first_node;
     typedef __rebind_pointer_t<_NodePtr, __first_node> __node_base_pointer;
     typedef _NodePtr __node_pointer;
 
 #if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
   typedef __node_base_pointer __next_pointer;
 #else
-  typedef typename conditional<
-      is_pointer<__node_pointer>::value,
-      __node_base_pointer,
-      __node_pointer>::type   __next_pointer;
+    typedef __conditional_t<is_pointer<__node_pointer>::value, __node_base_pointer, __node_pointer> __next_pointer;
 #endif
 
     __next_pointer    __next_;
 
     _LIBCPP_INLINE_VISIBILITY
     __next_pointer __ptr() _NOEXCEPT {
         return static_cast<__next_pointer>(
             pointer_traits<__node_base_pointer>::pointer_to(*this));

libcxx/include/__iterator/iterator_traits.h

 using _ITER_CONCEPT = typename __iter_concept_cache<_Iter>::type::template _Apply<_Iter>;
 
 
 template <class _Tp>
 struct __has_iterator_typedefs
 {
 private:
     template <class _Up> static false_type __test(...);
-    template <class _Up> static true_type __test(typename __void_t<typename _Up::iterator_category>::type* = 0,
-                                                 typename __void_t<typename _Up::difference_type>::type* = 0,
-                                                 typename __void_t<typename _Up::value_type>::type* = 0,
-                                                 typename __void_t<typename _Up::reference>::type* = 0,
-                                                 typename __void_t<typename _Up::pointer>::type* = 0);
+    template <class _Up> static true_type __test(__void_t<typename _Up::iterator_category>* = nullptr,
+                                                 __void_t<typename _Up::difference_type>* = nullptr,
+                                                 __void_t<typename _Up::value_type>* = nullptr,
+                                                 __void_t<typename _Up::reference>* = nullptr,
+                                                 __void_t<typename _Up::pointer>* = nullptr);
 public:
     static const bool value = decltype(__test<_Tp>(0,0,0,0,0))::value;
 };
 
 
 template <class _Tp>
 struct __has_iterator_category
 {

libcxx/include/__memory/allocator_traits.h

 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #define _LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(NAME, PROPERTY)                \
     template <class _Tp, class = void> struct NAME : false_type { };    \
-    template <class _Tp>               struct NAME<_Tp, typename __void_t<typename _Tp:: PROPERTY >::type> : true_type { }
+    template <class _Tp>               struct NAME<_Tp, __void_t<typename _Tp:: PROPERTY > > : true_type { }
 
 // __pointer
 _LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_pointer, pointer);
 template <class _Tp, class _Alloc,
           class _RawAlloc = __libcpp_remove_reference_t<_Alloc>,
           bool = __has_pointer<_RawAlloc>::value>
 struct __pointer {
     using type _LIBCPP_NODEBUG = typename _RawAlloc::pointer;
struct __is_always_equal<_Alloc, true> {
     using type _LIBCPP_NODEBUG = typename _Alloc::is_always_equal;
 };
 
 // __allocator_traits_rebind
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 template <class _Tp, class _Up, class = void>
 struct __has_rebind_other : false_type { };
 template <class _Tp, class _Up>
-struct __has_rebind_other<_Tp, _Up, typename __void_t<
-    typename _Tp::template rebind<_Up>::other
->::type> : true_type { };
+struct __has_rebind_other<_Tp, _Up, __void_t<typename _Tp::template rebind<_Up>::other> > : true_type { };
 
 template <class _Tp, class _Up, bool = __has_rebind_other<_Tp, _Up>::value>
 struct __allocator_traits_rebind {
     using type _LIBCPP_NODEBUG = typename _Tp::template rebind<_Up>::other;
 };
 template <template <class, class...> class _Alloc, class _Tp, class ..._Args, class _Up>
 struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, true> {
     using type _LIBCPP_NODEBUG = typename _Alloc<_Tp, _Args...>::template rebind<_Up>::other;

libcxx/include/__memory/pointer_traits.h

 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp, class = void>
 struct __has_element_type : false_type {};
 
 template <class _Tp>
-struct __has_element_type<_Tp,
-              typename __void_t<typename _Tp::element_type>::type> : true_type {};
+struct __has_element_type<_Tp, __void_t<typename _Tp::element_type> > : true_type {};
 
 template <class _Ptr, bool = __has_element_type<_Ptr>::value>
 struct __pointer_traits_element_type;
 
 template <class _Ptr>
 struct __pointer_traits_element_type<_Ptr, true>
 {
     typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;

 {
     typedef _LIBCPP_NODEBUG _Tp type;
 };
 
 template <class _Tp, class = void>
 struct __has_difference_type : false_type {};
 
 template <class _Tp>
-struct __has_difference_type<_Tp,
-            typename __void_t<typename _Tp::difference_type>::type> : true_type {};
+struct __has_difference_type<_Tp, __void_t<typename _Tp::difference_type> > : true_type {};
 
 template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
 struct __pointer_traits_difference_type
 {
     typedef _LIBCPP_NODEBUG ptrdiff_t type;
 };
 
 template <class _Ptr>
#else
     template <class _Up> struct rebind
         {typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
 #endif // _LIBCPP_CXX03_LANG
 
 private:
     struct __nat {};
 public:
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    static pointer pointer_to(typename conditional<is_void<element_type>::value,
-                                           __nat, element_type>::type& __r)
+    static pointer pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r)
         {return pointer::pointer_to(__r);}
 };
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
 {
     typedef _Tp*      pointer;
     typedef _Tp       element_type;
     typedef ptrdiff_t difference_type;
 
 #ifndef _LIBCPP_CXX03_LANG
     template <class _Up> using rebind = _Up*;
 #else
     template <class _Up> struct rebind {typedef _Up* other;};
 #endif
 
 private:
     struct __nat {};
 public:
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    static pointer pointer_to(typename conditional<is_void<element_type>::value,
-                                      __nat, element_type>::type& __r) _NOEXCEPT
+    static pointer pointer_to(__conditional_t<is_void<element_type>::value, __nat, element_type>& __r) _NOEXCEPT
         {return _VSTD::addressof(__r);}
 };
 
 #ifndef _LIBCPP_CXX03_LANG
 template <class _From, class _To>
 using __rebind_pointer_t = typename pointer_traits<_From>::template rebind<_To>;
 #else
 template <class _From, class _To>

libcxx/include/__random/independent_bits_engine.h

 private:
     _Engine __e_;
 
     static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
     static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
     static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");
 
     typedef typename _Engine::result_type _Engine_result_type;
-    typedef typename conditional
-        <
-            sizeof(_Engine_result_type) <= sizeof(result_type),
-                result_type,
-                _Engine_result_type
-        >::type _Working_result_type;
+    typedef __conditional_t<sizeof(_Engine_result_type) <= sizeof(result_type), result_type, _Engine_result_type>
+        _Working_result_type;
 #ifdef _LIBCPP_CXX03_LANG
     static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
                                           + _Working_result_type(1);
 #else
     static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
                                                             + _Working_result_type(1);
 #endif
     static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;

libcxx/include/__random/log2.h

 
 #endif // _LIBCPP_HAS_NO_INT128
 
 template <class _UIntType, _UIntType _Xp>
 struct __log2
 {
     static const size_t value = __log2_imp<
 #ifndef _LIBCPP_HAS_NO_INT128
-        typename conditional<
-                sizeof(_UIntType) <= sizeof(unsigned long long),
-                    unsigned long long,
-                    __uint128_t
-            >::type,
+        __conditional_t<sizeof(_UIntType) <= sizeof(unsigned long long), unsigned long long, __uint128_t>,
 #else
         unsigned long long,
 #endif // _LIBCPP_HAS_NO_INT128
-        _Xp, sizeof(_UIntType) * __CHAR_BIT__ - 1>::value;
+        _Xp,
+        sizeof(_UIntType) * __CHAR_BIT__ - 1>::value;
 };
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___RANDOM_LOG2_H

libcxx/include/__random/uniform_int_distribution.h

 class __independent_bits_engine
 {
 public:
     // types
     typedef _UIntType result_type;
 
 private:
     typedef typename _Engine::result_type _Engine_result_type;
-    typedef typename conditional
-        <
-            sizeof(_Engine_result_type) <= sizeof(result_type),
-                result_type,
-                _Engine_result_type
-        >::type _Working_result_type;
+    typedef __conditional_t<sizeof(_Engine_result_type) <= sizeof(result_type), result_type, _Engine_result_type>
+        _Working_result_type;
 
     _Engine& __e_;
     size_t __w_;
     size_t __w0_;
     size_t __n_;
     size_t __n0_;
     _Working_result_type __y0_;
     _Working_result_type __y1_;

 
 template<class _IntType>
 template<class _URNG>
 typename uniform_int_distribution<_IntType>::result_type
 uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
 _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
 {
     static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
-    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t), uint32_t,
-                                 __make_unsigned_t<result_type> >::type _UIntType;
+    typedef __conditional_t<sizeof(result_type) <= sizeof(uint32_t), uint32_t, __make_unsigned_t<result_type> >
+        _UIntType;
     const _UIntType _Rp = _UIntType(__p.b()) - _UIntType(__p.a()) + _UIntType(1);
     if (_Rp == 1)
         return __p.a();
     const size_t _Dt = numeric_limits<_UIntType>::digits;
     typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
     if (_Rp == 0)
         return static_cast<result_type>(_Eng(__g, _Dt)());
     size_t __w = _Dt - __countl_zero(_Rp) - 1;

libcxx/include/__tree

typedef __rebind_pointer_t<_VoidPtr, __node_base_type>
                                                              __node_base_pointer;
 
   typedef __tree_end_node<__node_base_pointer>                  __end_node_type;
   typedef __rebind_pointer_t<_VoidPtr, __end_node_type>
                                                              __end_node_pointer;
 #if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
   typedef __end_node_pointer __parent_pointer;
 #else
-  typedef typename conditional<
-      is_pointer<__end_node_pointer>::value,
-        __end_node_pointer,
-        __node_base_pointer>::type __parent_pointer;
+  typedef __conditional_t< is_pointer<__end_node_pointer>::value, __end_node_pointer, __node_base_pointer>
+      __parent_pointer;
 #endif
 
 private:
   static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
                   "_VoidPtr does not point to unqualified void type");
 };
 
 template <class _Tp, class _AllocPtr, class _KVTypes = __tree_key_value_types<_Tp>,
public:
   typedef _Tp                                                 __node_value_type;
   typedef __rebind_pointer_t<_VoidPtr, __node_value_type>
                                                       __node_value_type_pointer;
   typedef __rebind_pointer_t<_VoidPtr, const __node_value_type>
                                                 __const_node_value_type_pointer;
 #if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
   typedef typename __base::__end_node_pointer __iter_pointer;
 #else
-  typedef typename conditional<
-      is_pointer<__node_pointer>::value,
-        typename __base::__end_node_pointer,
-        __node_pointer>::type __iter_pointer;
+  typedef __conditional_t< is_pointer<__node_pointer>::value, typename __base::__end_node_pointer, __node_pointer>
+      __iter_pointer;
 #endif
 private:
     static_assert(!is_const<__node_type>::value,
                 "_NodePtr should never be a pointer to const");
     static_assert((is_same<__rebind_pointer_t<_VoidPtr, __node_type>,
                           _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
 };
 

libcxx/include/__type_traits/aligned_storage.h

 template <size_t _Align>
 struct _ALIGNAS(_Align) __fallback_overaligned {};
 
 template <class _TL, size_t _Align> struct __find_pod;
 
 template <class _Hp, size_t _Align>
 struct __find_pod<__type_list<_Hp, __nat>, _Align>
 {
-    typedef typename conditional<
-                             _Align == _Hp::value,
-                             typename _Hp::type,
-                             __fallback_overaligned<_Align>
-                         >::type type;
+    typedef __conditional_t<_Align == _Hp::value, typename _Hp::type, __fallback_overaligned<_Align> > type;
 };
 
 template <class _Hp, class _Tp, size_t _Align>
 struct __find_pod<__type_list<_Hp, _Tp>, _Align>
 {
-    typedef typename conditional<
-                             _Align == _Hp::value,
-                             typename _Hp::type,
-                             typename __find_pod<_Tp, _Align>::type
-                         >::type type;
+    typedef __conditional_t<_Align == _Hp::value, typename _Hp::type, typename __find_pod<_Tp, _Align>::type> type;
 };
 
 template <class _TL, size_t _Len> struct __find_max_align;
 
 template <class _Hp, size_t _Len>
 struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
 
 template <size_t _Len, size_t _A1, size_t _A2>

libcxx/include/__type_traits/can_extract_key.h

 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 // These traits are used in __tree and __hash_table
 struct __extract_key_fail_tag {};
 struct __extract_key_self_tag {};
 struct __extract_key_first_tag {};
 
-template <class _ValTy, class _Key,
-          class _RawValTy = __remove_const_ref_t<_ValTy> >
+template <class _ValTy, class _Key, class _RawValTy = __remove_const_ref_t<_ValTy> >
 struct __can_extract_key
-    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
-                  __extract_key_fail_tag>::type {};
+    : __conditional_t<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag, __extract_key_fail_tag> {};
 
 template <class _Pair, class _Key, class _First, class _Second>
 struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
-    : conditional<_IsSame<__remove_const_t<_First>, _Key>::value,
-                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
+    : __conditional_t<_IsSame<__remove_const_t<_First>, _Key>::value, __extract_key_first_tag, __extract_key_fail_tag> {
+};
 
 // __can_extract_map_key uses true_type/false_type instead of the tags.
 // It returns true if _Key != _ContainerValueTy (the container is a map not a set)
 // and _ValTy == _Key.
 template <class _ValTy, class _Key, class _ContainerValueTy,
           class _RawValTy = __remove_const_ref_t<_ValTy> >
 struct __can_extract_map_key
     : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};

libcxx/include/__type_traits/common_type.h

 struct __common_type2_imp : __common_type3<_Tp, _Up> {};
 #else
 template <class _Tp, class _Up, class = void>
 struct __common_type2_imp {};
 #endif
 
 // sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
 template <class _Tp, class _Up>
-struct __common_type2_imp<_Tp, _Up,
-                          typename __void_t<decltype(
-                                            true ? declval<_Tp>() : declval<_Up>()
-                                            )>::type>
+struct __common_type2_imp<_Tp, _Up, __void_t<decltype(true ? declval<_Tp>() : declval<_Up>())> >
 {
   typedef _LIBCPP_NODEBUG typename decay<decltype(
                          true ? declval<_Tp>() : declval<_Up>()
                          )>::type type;
 };
 
 template <class, class = void>
 struct __common_type_impl {};

 struct common_type {
   static_assert(sizeof(_Unused) == 0,
                 "common_type accepts at most 3 arguments in C++03");
 };
 #endif // _LIBCPP_CXX03_LANG
 
 template <class _Tp, class _Up>
 struct __common_type_impl<
-    __common_types<_Tp, _Up>,
-    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
+    __common_types<_Tp, _Up>, __void_t<typename common_type<_Tp, _Up>::type> >
 {
   typedef typename common_type<_Tp, _Up>::type type;
 };
 
 template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
 struct __common_type_impl<
     __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
-    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
+    __void_t<typename common_type<_Tp, _Up>::type> >
     : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
                                         _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
 };
 
 // bullet 1 - sizeof...(Tp) == 0
 
 template <>
 struct _LIBCPP_TEMPLATE_VIS common_type<> {};

libcxx/include/__type_traits/is_allocator.h

 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template<typename _Alloc, typename = void, typename = void>
 struct __is_allocator : false_type {};
 
 template<typename _Alloc>
 struct __is_allocator<_Alloc,
-       typename __void_t<typename _Alloc::value_type>::type,
-       typename __void_t<decltype(declval<_Alloc&>().allocate(size_t(0)))>::type
+       __void_t<typename _Alloc::value_type>,
+       __void_t<decltype(declval<_Alloc&>().allocate(size_t(0)))>
      >
    : true_type {};
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_IS_ALLOCATOR_H

libcxx/include/__type_traits/is_swappable.h

 template <class _Tp, class _Up>
 struct _LIBCPP_TEMPLATE_VIS is_swappable_with
     : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
 {
 };
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_swappable
-    : public conditional<
+    : public __conditional_t<
         __libcpp_is_referenceable<_Tp>::value,
         is_swappable_with<
             __add_lvalue_reference_t<_Tp>,
             __add_lvalue_reference_t<_Tp> >,
         false_type
-    >::type
+    >
 {
 };
 
 template <class _Tp, class _Up>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
     : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
 {
 };
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
-    : public conditional<
+    : public __conditional_t<
         __libcpp_is_referenceable<_Tp>::value,
         is_nothrow_swappable_with<
             __add_lvalue_reference_t<_Tp>,
             __add_lvalue_reference_t<_Tp> >,
         false_type
-    >::type
+    >
 {
 };
 
 template <class _Tp, class _Up>
 inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
 
 template <class _Tp>
 inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;

libcxx/include/__type_traits/maybe_const.h

 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template<bool _Const, class _Tp>
-using __maybe_const = typename conditional<_Const, const _Tp, _Tp>::type;
+using __maybe_const = __conditional_t<_Const, const _Tp, _Tp>;
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_MAYBE_CONST_H

libcxx/include/__type_traits/void_t.h

 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER > 14
 template <class...> using void_t = void;
 #endif
 
-template <class>
-struct __void_t { typedef void type; };
+template <class...>
+using __void_t = void;
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_VOID_T_H

libcxx/include/__utility/move.h

 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __libcpp_remove_reference_t<_Tp>&&
 move(_Tp&& __t) _NOEXCEPT {
   typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tp> _Up;
   return static_cast<_Up&&>(__t);
 }
 
 template <class _Tp>
 using __move_if_noexcept_result_t =
-    typename conditional<!is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value, const _Tp&,
-                         _Tp&&>::type;
+    __conditional_t<!is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value, const _Tp&, _Tp&&>;
 
 template <class _Tp>
 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14 __move_if_noexcept_result_t<_Tp>
 move_if_noexcept(_Tp& __x) _NOEXCEPT {
   return _VSTD::move(__x);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___UTILITY_MOVE_H

libcxx/include/__utility/pair.h

struct _CheckTupleLikeConstructor {
 
         template <class _Tuple>
         static constexpr bool __enable_assign() {
             return __tuple_assignable<_Tuple, pair>::value;
         }
     };
 
     template <class _Tuple>
-    using _CheckTLC _LIBCPP_NODEBUG = typename conditional<
+    using _CheckTLC _LIBCPP_NODEBUG = __conditional_t<
         __tuple_like_with_size<_Tuple, 2>::value
             && !is_same<typename decay<_Tuple>::type, pair>::value,
         _CheckTupleLikeConstructor,
         __check_tuple_constructor_fail
-    >::type;
+    >;
 
     template<bool _Dummy = true, typename enable_if<
             _CheckArgsDep<_Dummy>::__enable_explicit_default()
     >::type* = nullptr>
     explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
     pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
                       is_nothrow_default_constructible<second_type>::value)
         : first(), second() {}
pair(piecewise_construct_t __pc,
          tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
         _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
                     is_nothrow_constructible<second_type, _Args2...>::value))
         : pair(__pc, __first_args, __second_args,
                 typename __make_tuple_indices<sizeof...(_Args1)>::type(),
                 typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    pair& operator=(typename conditional<
+    pair& operator=(__conditional_t<
                         is_copy_assignable<first_type>::value &&
                         is_copy_assignable<second_type>::value,
-                    pair, __nat>::type const& __p)
+                    pair, __nat> const& __p)
         _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
                    is_nothrow_copy_assignable<second_type>::value)
     {
         first = __p.first;
         second = __p.second;
         return *this;
     }
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    pair& operator=(typename conditional<
+    pair& operator=(__conditional_t<
                         is_move_assignable<first_type>::value &&
                         is_move_assignable<second_type>::value,
-                    pair, __nat>::type&& __p)
+                    pair, __nat>&& __p)
         _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
                    is_nothrow_move_assignable<second_type>::value)
     {
         first = _VSTD::forward<first_type>(__p.first);
         second = _VSTD::forward<second_type>(__p.second);
         return *this;
     }
 

libcxx/include/array

struct _LIBCPP_TEMPLATE_VIS array<_Tp, 0>
     typedef const value_type*                     const_iterator;
     typedef value_type*                           pointer;
     typedef const value_type*                     const_pointer;
     typedef size_t                                size_type;
     typedef ptrdiff_t                             difference_type;
     typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
     typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
 
-    typedef typename conditional<is_const<_Tp>::value, const char,
-                                char>::type _CharType;
+    typedef __conditional_t<is_const<_Tp>::value, const char, char> _CharType;
 
     struct  _ArrayInStructT { _Tp __data_[1]; };
     _ALIGNAS_TYPE(_ArrayInStructT) _CharType __elems_[sizeof(_ArrayInStructT)];
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
     value_type* data() _NOEXCEPT {return nullptr;}
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
     const value_type* data() const _NOEXCEPT {return nullptr;}

libcxx/include/atomic

 
 #ifdef __cpp_lib_atomic_is_always_lock_free
 # define _LIBCPP_CONTENTION_LOCK_FREE ::std::__libcpp_is_always_lock_free<__cxx_contention_t>::__value
 #else
 # define _LIBCPP_CONTENTION_LOCK_FREE false
 #endif
 
 #if ATOMIC_LLONG_LOCK_FREE == 2
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>::type          __libcpp_signed_lock_free;
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long>::type __libcpp_unsigned_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>          __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long> __libcpp_unsigned_lock_free;
 #elif ATOMIC_INT_LOCK_FREE == 2
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>::type                __libcpp_signed_lock_free;
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>::type       __libcpp_unsigned_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>                __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>       __libcpp_unsigned_lock_free;
 #elif ATOMIC_SHORT_LOCK_FREE == 2
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>::type              __libcpp_signed_lock_free;
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>::type     __libcpp_unsigned_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>              __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>     __libcpp_unsigned_lock_free;
 #elif ATOMIC_CHAR_LOCK_FREE == 2
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>::type               __libcpp_signed_lock_free;
-typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>::type      __libcpp_unsigned_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>               __libcpp_signed_lock_free;
+typedef __conditional_t<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>      __libcpp_unsigned_lock_free;
 #else
     // No signed/unsigned lock-free types
 #define _LIBCPP_NO_LOCK_FREE_TYPES
 #endif
 
 #if !defined(_LIBCPP_NO_LOCK_FREE_TYPES)
 typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
 typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;

libcxx/include/experimental/__memory

 
 template <class _Tp, class _Alloc, class ..._Args>
 struct __lfts_uses_alloc_ctor_imp<true, _Tp, _Alloc, _Args...>
 {
     static const bool __ic_first
         = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
 
     static const bool __ic_second =
-        conditional<
+        __conditional_t<
             __ic_first,
             false_type,
             is_constructible<_Tp, _Args..., _Alloc>
-        >::type::value;
+        >::value;
 
     static_assert(__ic_first || __ic_second,
                   "Request for uses allocator construction is ill-formed");
 
     static const int value = __ic_first ? 1 : 2;
 };
 
 template <class _Tp, class _Alloc, class ..._Args>

libcxx/include/experimental/coroutine

 #ifndef _LIBCPP_HAS_NO_EXPERIMENTAL_COROUTINES
 
 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES
 
 template <class _Tp, class = void>
 struct __coroutine_traits_sfinae {};
 
 template <class _Tp>
-struct __coroutine_traits_sfinae<
-    _Tp, typename __void_t<typename _Tp::promise_type>::type>
+struct __coroutine_traits_sfinae<_Tp, __void_t<typename _Tp::promise_type> >
 {
   using promise_type = typename _Tp::promise_type;
 };
 
 template <typename _Ret, typename... _Args>
 struct coroutine_traits
     : public __coroutine_traits_sfinae<_Ret>
 {

libcxx/include/forward_list

struct __forward_node_traits {
   typedef _NodePtr                                              __node_pointer;
   typedef __forward_begin_node<_NodePtr>                        __begin_node;
   typedef __rebind_pointer_t<_NodePtr, __begin_node>            __begin_node_pointer;
   typedef __rebind_pointer_t<_NodePtr, void>                    __void_pointer;
 
 #if defined(_LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB)
   typedef __begin_node_pointer __iter_node_pointer;
 #else
-  typedef typename conditional<
-          is_pointer<__void_pointer>::value,
-          __begin_node_pointer,
-          __node_pointer
-    >::type __iter_node_pointer;
+  typedef __conditional_t<is_pointer<__void_pointer>::value, __begin_node_pointer, __node_pointer>
+      __iter_node_pointer;
 #endif
 
-  typedef typename conditional<
-          is_same<__iter_node_pointer, __node_pointer>::value,
-          __begin_node_pointer,
-          __node_pointer
-    >::type __non_iter_node_pointer;
+  typedef __conditional_t<is_same<__iter_node_pointer, __node_pointer>::value, __begin_node_pointer, __node_pointer>
+      __non_iter_node_pointer;
 
   _LIBCPP_INLINE_VISIBILITY
   static __iter_node_pointer __as_iter_node(__iter_node_pointer __p) {
       return __p;
   }
   _LIBCPP_INLINE_VISIBILITY
   static __iter_node_pointer __as_iter_node(__non_iter_node_pointer __p) {
       return static_cast<__iter_node_pointer>(static_cast<__void_pointer>(__p));
struct __forward_begin_node
 
     _LIBCPP_INLINE_VISIBILITY
     __begin_node_pointer __next_as_begin() const {
         return static_cast<__begin_node_pointer>(__next_);
     }
 };
 
 template <class _Tp, class _VoidPtr>
-struct _LIBCPP_HIDDEN __begin_node_of
-{
-    typedef __forward_begin_node<
-        __rebind_pointer_t<_VoidPtr, __forward_list_node<_Tp, _VoidPtr> >
-    > type;
-};
+using __begin_node_of = __forward_begin_node<__rebind_pointer_t<_VoidPtr, __forward_list_node<_Tp, _VoidPtr> > >;
 
 template <class _Tp, class _VoidPtr>
 struct _LIBCPP_STANDALONE_DEBUG __forward_list_node
-    : public __begin_node_of<_Tp, _VoidPtr>::type
+    : public __begin_node_of<_Tp, _VoidPtr>
 {
     typedef _Tp value_type;
 
     value_type __value_;
 };
 
 
 template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS forward_list;

 class __forward_list_base
 {
 protected:
     typedef _Tp    value_type;
     typedef _Alloc allocator_type;
 
     typedef typename allocator_traits<allocator_type>::void_pointer  void_pointer;
     typedef __forward_list_node<value_type, void_pointer>            __node;
-    typedef typename __begin_node_of<value_type, void_pointer>::type __begin_node;
+    typedef __begin_node_of<value_type, void_pointer>                __begin_node;
     typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>, __node>::type __node_allocator;
     typedef allocator_traits<__node_allocator>        __node_traits;
     typedef typename __node_traits::pointer           __node_pointer;
 
     typedef typename __rebind_alloc_helper<
         allocator_traits<allocator_type>, __begin_node
     >::type                                           __begin_node_allocator;
     typedef typename allocator_traits<__begin_node_allocator>::pointer

libcxx/include/list

struct __list_node_pointer_traits {
   typedef __rebind_pointer_t<_VoidPtr, __list_node<_Tp, _VoidPtr> >
         __node_pointer;
   typedef __rebind_pointer_t<_VoidPtr, __list_node_base<_Tp, _VoidPtr> >
         __base_pointer;
 
 #if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
   typedef __base_pointer __link_pointer;
 #else
-  typedef typename conditional<
-          is_pointer<_VoidPtr>::value,
-          __base_pointer,
-          __node_pointer
-  >::type __link_pointer;
+  typedef __conditional_t<is_pointer<_VoidPtr>::value, __base_pointer, __node_pointer> __link_pointer;
 #endif
 
-  typedef typename conditional<
-          is_same<__link_pointer, __node_pointer>::value,
-          __base_pointer,
-          __node_pointer
-  >::type __non_link_pointer;
+  typedef __conditional_t<is_same<__link_pointer, __node_pointer>::value, __base_pointer, __node_pointer>
+      __non_link_pointer;
 
   static _LIBCPP_INLINE_VISIBILITY
   __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) {
       return __p;
   }
 
   static _LIBCPP_INLINE_VISIBILITY
   __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {

libcxx/include/ostream

 {
     return __os << __p.get();
 }
 
 template<class _CharT, class _Traits, class _Yp, class _Dp>
 inline _LIBCPP_INLINE_VISIBILITY
 typename enable_if
 <
-    is_same<void, typename __void_t<decltype((declval<basic_ostream<_CharT, _Traits>&>() << declval<typename unique_ptr<_Yp, _Dp>::pointer>()))>::type>::value,
+    is_same<void, __void_t<decltype((declval<basic_ostream<_CharT, _Traits>&>() << declval<typename unique_ptr<_Yp, _Dp>::pointer>()))> >::value,
     basic_ostream<_CharT, _Traits>&
 >::type
 operator<<(basic_ostream<_CharT, _Traits>& __os, unique_ptr<_Yp, _Dp> const& __p)
 {
     return __os << __p.get();
 }
 
 template <class _CharT, class _Traits, size_t _Size>