diff --git a/libcxx/include/__config b/libcxx/include/__config
index 91bc6fc21df8ec..108f700823cbfb 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -162,16 +162,6 @@ _LIBCPP_HARDENING_MODE_DEBUG
 #    define _LIBCPP_CXX03_LANG
 #  endif
 
-// TODO: Remove once we switch to GCC 14
-#  ifndef __has_extension
-#    define __has_extension(__x) 0
-#  endif
-
-// TODO: Remove once we switch to GCC 14
-#  ifndef __has_feature
-#    define __has_feature(__x) 0
-#  endif
-
 #  ifndef __has_constexpr_builtin
 #    define __has_constexpr_builtin(x) 0
 #  endif
@@ -348,44 +338,30 @@ typedef __char32_t char32_t;
 
 #  define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)
 
-#  if defined(_LIBCPP_COMPILER_CLANG_BASED)
-
 // Objective-C++ features (opt-in)
-#    if __has_feature(objc_arc)
-#      define _LIBCPP_HAS_OBJC_ARC
-#    endif
-
-#    if __has_feature(objc_arc_weak)
-#      define _LIBCPP_HAS_OBJC_ARC_WEAK
-#    endif
-
-#    if __has_extension(blocks)
-#      define _LIBCPP_HAS_EXTENSION_BLOCKS
-#    endif
-
-#    if defined(_LIBCPP_HAS_EXTENSION_BLOCKS) && defined(__APPLE__)
-#      define _LIBCPP_HAS_BLOCKS_RUNTIME
-#    endif
-
-#    if !__has_feature(address_sanitizer)
-#      define _LIBCPP_HAS_NO_ASAN
-#    endif
-
-#    define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))
+#  if __has_feature(objc_arc)
+#    define _LIBCPP_HAS_OBJC_ARC
+#  endif
 
-#    define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
+#  if __has_feature(objc_arc_weak)
+#    define _LIBCPP_HAS_OBJC_ARC_WEAK
+#  endif
 
-#  elif defined(_LIBCPP_COMPILER_GCC)
+#  if __has_extension(blocks)
+#    define _LIBCPP_HAS_EXTENSION_BLOCKS
+#  endif
 
-#    if !defined(__SANITIZE_ADDRESS__)
-#      define _LIBCPP_HAS_NO_ASAN
-#    endif
+#  if defined(_LIBCPP_HAS_EXTENSION_BLOCKS) && defined(__APPLE__)
+#    define _LIBCPP_HAS_BLOCKS_RUNTIME
+#  endif
 
-#    define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))
+#  if !__has_feature(address_sanitizer)
+#    define _LIBCPP_HAS_NO_ASAN
+#  endif
 
-#    define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
+#  define _LIBCPP_ALWAYS_INLINE __attribute__((__always_inline__))
 
-#  endif // _LIBCPP_COMPILER_[CLANG|GCC]
+#  define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
 
 #  if defined(_LIBCPP_OBJECT_FORMAT_COFF)
 
diff --git a/libcxx/include/__tuple/tuple_element.h b/libcxx/include/__tuple/tuple_element.h
index 55b3b47619f648..9127c47dc8f1a5 100644
--- a/libcxx/include/__tuple/tuple_element.h
+++ b/libcxx/include/__tuple/tuple_element.h
@@ -40,32 +40,6 @@ struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, const volatile _Tp> {
 
 #ifndef _LIBCPP_CXX03_LANG
 
-#  if !__has_builtin(__type_pack_element)
-
-namespace __indexer_detail {
-
-template <size_t _Idx, class _Tp>
-struct __indexed {
-  using type _LIBCPP_NODEBUG = _Tp;
-};
-
-template <class _Types, class _Indexes>
-struct __indexer;
-
-template <class... _Types, size_t... _Idx>
-struct __indexer<__tuple_types<_Types...>, __tuple_indices<_Idx...>> : __indexed<_Idx, _Types>... {};
-
-template <size_t _Idx, class _Tp>
-__indexed<_Idx, _Tp> __at_index(__indexed<_Idx, _Tp> const&);
-
-} // namespace __indexer_detail
-
-template <size_t _Idx, class... _Types>
-using __type_pack_element _LIBCPP_NODEBUG = typename decltype(__indexer_detail::__at_index<_Idx>(
-    __indexer_detail::__indexer< __tuple_types<_Types...>,
-                                 typename __make_tuple_indices<sizeof...(_Types)>::type >{}))::type;
-#  endif
-
 template <size_t _Ip, class... _Types>
 struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, __tuple_types<_Types...> > {
   static_assert(_Ip < sizeof...(_Types), "tuple_element index out of range");
diff --git a/libcxx/include/__type_traits/is_function.h b/libcxx/include/__type_traits/is_function.h
index f09f19adf4aab4..98fedd0ad96d9b 100644
--- a/libcxx/include/__type_traits/is_function.h
+++ b/libcxx/include/__type_traits/is_function.h
@@ -11,8 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_const.h>
-#include <__type_traits/is_reference.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,22 +18,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_function)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_function : integral_constant<bool, __is_function(_Tp)> {};
 
-#else
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_function
-    : public integral_constant<bool, !(is_reference<_Tp>::value || is_const<const _Tp>::value)> {};
-
-#endif // __has_builtin(__is_function)
-
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-inline constexpr bool is_function_v = is_function<_Tp>::value;
+inline constexpr bool is_function_v = __is_function(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_member_function_pointer.h b/libcxx/include/__type_traits/is_member_function_pointer.h
index 11c8a00c997567..037d5ca04ab0b2 100644
--- a/libcxx/include/__type_traits/is_member_function_pointer.h
+++ b/libcxx/include/__type_traits/is_member_function_pointer.h
@@ -11,9 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_function.h>
-#include <__type_traits/remove_cv.h>
-#include <cstddef>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,21 +18,6 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp>
-struct __libcpp_is_member_pointer {
-  enum { __is_member = false, __is_func = false, __is_obj = false };
-};
-template <class _Tp, class _Up>
-struct __libcpp_is_member_pointer<_Tp _Up::*> {
-  enum {
-    __is_member = true,
-    __is_func   = is_function<_Tp>::value,
-    __is_obj    = !__is_func,
-  };
-};
-
-#if __has_builtin(__is_member_function_pointer)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer : _BoolConstant<__is_member_function_pointer(_Tp)> {};
 
@@ -44,19 +26,6 @@ template <class _Tp>
 inline constexpr bool is_member_function_pointer_v = __is_member_function_pointer(_Tp);
 #  endif
 
-#else // __has_builtin(__is_member_function_pointer)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
-    : public _BoolConstant<__libcpp_is_member_pointer<__remove_cv_t<_Tp> >::__is_func> {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_member_function_pointer_v = is_member_function_pointer<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_member_function_pointer)
-
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_MEMBER_FUNCTION_POINTER_H
diff --git a/libcxx/include/__type_traits/is_member_object_pointer.h b/libcxx/include/__type_traits/is_member_object_pointer.h
index 9141f9da530f25..555794bfe03876 100644
--- a/libcxx/include/__type_traits/is_member_object_pointer.h
+++ b/libcxx/include/__type_traits/is_member_object_pointer.h
@@ -18,8 +18,6 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_member_object_pointer)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer : _BoolConstant<__is_member_object_pointer(_Tp)> {};
 
@@ -28,19 +26,6 @@ template <class _Tp>
 inline constexpr bool is_member_object_pointer_v = __is_member_object_pointer(_Tp);
 #  endif
 
-#else // __has_builtin(__is_member_object_pointer)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
-    : public _BoolConstant<__libcpp_is_member_pointer<__remove_cv_t<_Tp> >::__is_obj> {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_member_object_pointer_v = is_member_object_pointer<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_member_object_pointer)
-
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_MEMBER_FUNCTION_POINTER_H
diff --git a/libcxx/include/__type_traits/is_member_pointer.h b/libcxx/include/__type_traits/is_member_pointer.h
index 4ca01d1c2fc89d..149634fde75846 100644
--- a/libcxx/include/__type_traits/is_member_pointer.h
+++ b/libcxx/include/__type_traits/is_member_pointer.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_member_function_pointer.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -19,8 +18,6 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_member_pointer)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> {};
 
@@ -29,19 +26,6 @@ template <class _Tp>
 inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
 #  endif
 
-#else // __has_builtin(__is_member_pointer)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_member_pointer
-    : public _BoolConstant<__libcpp_is_member_pointer<__remove_cv_t<_Tp> >::__is_member> {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_member_pointer)
-
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_MEMBER_POINTER_H
diff --git a/libcxx/include/__type_traits/is_nothrow_constructible.h b/libcxx/include/__type_traits/is_nothrow_constructible.h
index 2f7ed8487e76bb..58d2b2475140b6 100644
--- a/libcxx/include/__type_traits/is_nothrow_constructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_constructible.h
@@ -13,10 +13,6 @@
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/add_rvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_constructible.h>
-#include <__type_traits/is_reference.h>
-#include <__utility/declval.h>
-#include <cstddef>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -24,85 +20,28 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-// GCC is disabled due to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106611
-#if __has_builtin(__is_nothrow_constructible) && !defined(_LIBCPP_COMPILER_GCC)
-
 template < class _Tp, class... _Args>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
     : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
-#else
-
-template <bool, bool, class _Tp, class... _Args>
-struct __libcpp_is_nothrow_constructible;
-
-template <class _Tp, class... _Args>
-struct __libcpp_is_nothrow_constructible</*is constructible*/ true, /*is reference*/ false, _Tp, _Args...>
-    : public integral_constant<bool, noexcept(_Tp(std::declval<_Args>()...))> {};
-
-template <class _Tp>
-void __implicit_conversion_to(_Tp) noexcept {}
-
-template <class _Tp, class _Arg>
-struct __libcpp_is_nothrow_constructible</*is constructible*/ true, /*is reference*/ true, _Tp, _Arg>
-    : public integral_constant<bool, noexcept(std::__implicit_conversion_to<_Tp>(std::declval<_Arg>()))> {};
-
-template <class _Tp, bool _IsReference, class... _Args>
-struct __libcpp_is_nothrow_constructible</*is constructible*/ false, _IsReference, _Tp, _Args...> : public false_type {
-};
-
-template <class _Tp, class... _Args>
-struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
-    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value,
-                                        is_reference<_Tp>::value,
-                                        _Tp,
-                                        _Args...> {};
-
-template <class _Tp, size_t _Ns>
-struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
-    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp> {};
-
-#endif // __has_builtin(__is_nothrow_constructible)
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp, class... _Args>
 inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
 #endif
 
-// TODO: remove this implementation once https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106611 is fixed
-#ifdef _LIBCPP_COMPILER_GCC
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
-    : public is_nothrow_constructible<_Tp, __add_lvalue_reference_t<const _Tp> > {};
-
-#else // _LIBCPP_COMPILER_GCC
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
     : public integral_constant< bool, __is_nothrow_constructible(_Tp, __add_lvalue_reference_t<const _Tp>)> {};
 
-#endif // _LIBCPP_COMPILER_GCC
-
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp>
 inline constexpr bool is_nothrow_copy_constructible_v = is_nothrow_copy_constructible<_Tp>::value;
 #endif
 
-// TODO: remove this implementation once https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106611 is fixed
-#ifndef _LIBCPP_COMPILER_GCC
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
     : public integral_constant<bool, __is_nothrow_constructible(_Tp, __add_rvalue_reference_t<_Tp>)> {};
 
-#else // _LIBCPP_COMPILER_GCC
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
-    : public is_nothrow_constructible<_Tp, __add_rvalue_reference_t<_Tp> > {};
-
-#endif // _LIBCPP_COMPILER_GCC
-
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp>
 inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<_Tp>::value;
diff --git a/libcxx/include/__type_traits/is_object.h b/libcxx/include/__type_traits/is_object.h
index 5ac1d854a69587..ec04508402ce51 100644
--- a/libcxx/include/__type_traits/is_object.h
+++ b/libcxx/include/__type_traits/is_object.h
@@ -11,10 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_array.h>
-#include <__type_traits/is_class.h>
-#include <__type_traits/is_scalar.h>
-#include <__type_traits/is_union.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -22,30 +18,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_object)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> {};
 
-#  if _LIBCPP_STD_VER >= 17
+#if _LIBCPP_STD_VER >= 17
 template <class _Tp>
 inline constexpr bool is_object_v = __is_object(_Tp);
-#  endif
-
-#else // __has_builtin(__is_object)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_object
-    : public integral_constant<bool,
-                               is_scalar<_Tp>::value || is_array<_Tp>::value || is_union<_Tp>::value ||
-                                   is_class<_Tp>::value > {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_object_v = is_object<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_object)
+#endif
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_reference.h b/libcxx/include/__type_traits/is_reference.h
index 42853d47903958..cc157a438e4913 100644
--- a/libcxx/include/__type_traits/is_reference.h
+++ b/libcxx/include/__type_traits/is_reference.h
@@ -18,27 +18,30 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_lvalue_reference) && __has_builtin(__is_rvalue_reference) && __has_builtin(__is_reference)
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> {};
 
+#if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> {};
+inline constexpr bool is_reference_v = __is_reference(_Tp);
+#endif
+
+#if __has_builtin(__is_lvalue_reference) && __has_builtin(__is_rvalue_reference)
 
 template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> {};
+struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> {};
 
 template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> {};
+struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> {};
 
 #  if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-inline constexpr bool is_reference_v = __is_reference(_Tp);
-template <class _Tp>
 inline constexpr bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
 template <class _Tp>
 inline constexpr bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
 #  endif
 
-#else // __has_builtin(__is_lvalue_reference) && etc...
+#else // __has_builtin(__is_lvalue_reference)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : public false_type {};
@@ -50,17 +53,7 @@ struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : public false_type {};
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
 
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_reference : public false_type {};
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&> : public true_type {};
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
-
 #  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_reference_v = is_reference<_Tp>::value;
-
 template <class _Tp>
 inline constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
 
@@ -68,7 +61,7 @@ template <class _Tp>
 inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
 #  endif
 
-#endif // __has_builtin(__is_lvalue_reference) && etc...
+#endif // __has_builtin(__is_lvalue_reference)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_scoped_enum.h b/libcxx/include/__type_traits/is_scoped_enum.h
index 1db88e13356e83..cb3e25cf573317 100644
--- a/libcxx/include/__type_traits/is_scoped_enum.h
+++ b/libcxx/include/__type_traits/is_scoped_enum.h
@@ -11,9 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_convertible.h>
-#include <__type_traits/is_enum.h>
-#include <__type_traits/underlying_type.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -23,31 +20,12 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 23
 
-// TODO: GCC and Clang both have this builtin. Remove the false case once we've updated to GCC 14.
-#  if __has_builtin(__is_scoped_enum)
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_scoped_enum : bool_constant<__is_scoped_enum(_Tp)> {};
 
 template <class _Tp>
 inline constexpr bool is_scoped_enum_v = __is_scoped_enum(_Tp);
 
-#  else
-
-template <class _Tp, bool = is_enum_v<_Tp> >
-struct __is_scoped_enum_helper : false_type {};
-
-template <class _Tp>
-struct __is_scoped_enum_helper<_Tp, true> : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_scoped_enum : public __is_scoped_enum_helper<_Tp> {};
-
-template <class _Tp>
-inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
-
-#  endif // __has_builtin(__is_scoped_enum)
-
 #endif // _LIBCPP_STD_VER >= 23
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/test/libcxx/transitive_includes/cxx03.csv b/libcxx/test/libcxx/transitive_includes/cxx03.csv
index c720a0c9a05ec7..65c805cd86b76d 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx03.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx03.csv
@@ -855,7 +855,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx11.csv b/libcxx/test/libcxx/transitive_includes/cxx11.csv
index b00436a1be7f7c..bf353b2dd4ce47 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx11.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx11.csv
@@ -862,7 +862,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx14.csv b/libcxx/test/libcxx/transitive_includes/cxx14.csv
index 4b8c12929de0d6..fa6e44873fc126 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx14.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx14.csv
@@ -865,7 +865,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx17.csv b/libcxx/test/libcxx/transitive_includes/cxx17.csv
index a51a7e2de1d380..e03f74f50b9144 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx17.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx17.csv
@@ -866,7 +866,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx20.csv b/libcxx/test/libcxx/transitive_includes/cxx20.csv
index 5280d75cbf2e1f..37cd4e58e7fcad 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx20.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx20.csv
@@ -873,7 +873,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx23.csv b/libcxx/test/libcxx/transitive_includes/cxx23.csv
index 4cad0fdf31bded..098752e8699f79 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx23.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx23.csv
@@ -599,7 +599,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map
diff --git a/libcxx/test/libcxx/transitive_includes/cxx26.csv b/libcxx/test/libcxx/transitive_includes/cxx26.csv
index 4cad0fdf31bded..098752e8699f79 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx26.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx26.csv
@@ -599,7 +599,6 @@ string_view version
 strstream istream
 strstream ostream
 strstream version
-syncstream cstddef
 syncstream ios
 syncstream iosfwd
 syncstream map