diff --git a/libcxx/include/__type_traits/alignment_of.h b/libcxx/include/__type_traits/alignment_of.h
--- a/libcxx/include/__type_traits/alignment_of.h
+++ b/libcxx/include/__type_traits/alignment_of.h
@@ -24,7 +24,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
+inline constexpr size_t alignment_of_v = _LIBCPP_ALIGNOF(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/apply_cv.h b/libcxx/include/__type_traits/apply_cv.h
--- a/libcxx/include/__type_traits/apply_cv.h
+++ b/libcxx/include/__type_traits/apply_cv.h
@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_APPLY_CV_H
 
 #include <__config>
-#include <__type_traits/integral_constant.h>
 #include <__type_traits/is_const.h>
 #include <__type_traits/is_volatile.h>
 #include <__type_traits/remove_reference.h>
diff --git a/libcxx/include/__type_traits/decay.h b/libcxx/include/__type_traits/decay.h
--- a/libcxx/include/__type_traits/decay.h
+++ b/libcxx/include/__type_traits/decay.h
@@ -12,7 +12,6 @@
 #include <__config>
 #include <__type_traits/add_pointer.h>
 #include <__type_traits/conditional.h>
-#include <__type_traits/integral_constant.h>
 #include <__type_traits/is_array.h>
 #include <__type_traits/is_function.h>
 #include <__type_traits/is_referenceable.h>
diff --git a/libcxx/include/__type_traits/disjunction.h b/libcxx/include/__type_traits/disjunction.h
--- a/libcxx/include/__type_traits/disjunction.h
+++ b/libcxx/include/__type_traits/disjunction.h
@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_DISJUNCTION_H
 
 #include <__config>
-#include <__type_traits/conditional.h>
 #include <__type_traits/integral_constant.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__type_traits/extent.h b/libcxx/include/__type_traits/extent.h
--- a/libcxx/include/__type_traits/extent.h
+++ b/libcxx/include/__type_traits/extent.h
@@ -19,7 +19,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__array_extent)
+#if __has_builtin(__array_extent)
 
 template<class _Tp, size_t _Dim = 0>
 struct _LIBCPP_TEMPLATE_VIS extent
@@ -30,7 +30,7 @@
 inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
 #endif
 
-#else // __has_keyword(__array_extent)
+#else // __has_builtin(__array_extent)
 
 template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
     : public integral_constant<size_t, 0> {};
@@ -48,7 +48,7 @@
 inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
 #endif
 
-#endif // __has_keyword(__array_extent)
+#endif // __has_builtin(__array_extent)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/has_virtual_destructor.h b/libcxx/include/__type_traits/has_virtual_destructor.h
--- a/libcxx/include/__type_traits/has_virtual_destructor.h
+++ b/libcxx/include/__type_traits/has_virtual_destructor.h
@@ -18,21 +18,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
-
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
     : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
 
-#else
-
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
-    : public false_type {};
-
-#endif
-
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool has_virtual_destructor_v = has_virtual_destructor<_Tp>::value;
+inline constexpr bool has_virtual_destructor_v = __has_virtual_destructor(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_array.h b/libcxx/include/__type_traits/is_array.h
--- a/libcxx/include/__type_traits/is_array.h
+++ b/libcxx/include/__type_traits/is_array.h
@@ -21,7 +21,7 @@
 
 // TODO: Clang incorrectly reports that __is_array is true for T[0].
 //       Re-enable the branch once https://llvm.org/PR54705 is fixed.
-#if __has_keyword(__is_array) && 0
+#if __has_builtin(__is_array) && 0
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
@@ -45,7 +45,7 @@
 inline constexpr bool is_array_v = is_array<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_array)
+#endif // __has_builtin(__is_array)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_assignable.h b/libcxx/include/__type_traits/is_assignable.h
--- a/libcxx/include/__type_traits/is_assignable.h
+++ b/libcxx/include/__type_traits/is_assignable.h
@@ -18,10 +18,6 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG _Tp type; };
-
-#if __has_keyword(__is_assignable)
-
 template<class _Tp, class _Up>
 struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
 
@@ -30,37 +26,6 @@
 inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Arg);
 #endif
 
-#else // __has_keyword(__is_assignable)
-
-template <class _Tp, class _Arg>
-typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
-__is_assignable_test(int);
-
-template <class, class>
-false_type __is_assignable_test(...);
-
-
-template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
-struct __is_assignable_imp
-    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
-
-template <class _Tp, class _Arg>
-struct __is_assignable_imp<_Tp, _Arg, true>
-    : public false_type
-{
-};
-
-template <class _Tp, class _Arg>
-struct is_assignable
-    : public __is_assignable_imp<_Tp, _Arg> {};
-
-#if _LIBCPP_STD_VER > 14
-template <class _Tp, class _Arg>
-inline constexpr bool is_assignable_v = is_assignable<_Tp, _Arg>::value;
-#endif
-
-#endif // __has_keyword(__is_assignable)
-
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_ASSIGNABLE_H
diff --git a/libcxx/include/__type_traits/is_class.h b/libcxx/include/__type_traits/is_class.h
--- a/libcxx/include/__type_traits/is_class.h
+++ b/libcxx/include/__type_traits/is_class.h
@@ -11,8 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_union.h>
-#include <__type_traits/remove_cv.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__type_traits/is_compound.h b/libcxx/include/__type_traits/is_compound.h
--- a/libcxx/include/__type_traits/is_compound.h
+++ b/libcxx/include/__type_traits/is_compound.h
@@ -19,7 +19,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_compound)
+#if __has_builtin(__is_compound)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
@@ -29,7 +29,7 @@
 inline constexpr bool is_compound_v = __is_compound(_Tp);
 #endif
 
-#else // __has_keyword(__is_compound)
+#else // __has_builtin(__is_compound)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
     : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
@@ -39,7 +39,7 @@
 inline constexpr bool is_compound_v = is_compound<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_compound)
+#endif // __has_builtin(__is_compound)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_const.h b/libcxx/include/__type_traits/is_const.h
--- a/libcxx/include/__type_traits/is_const.h
+++ b/libcxx/include/__type_traits/is_const.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_const)
+#if __has_builtin(__is_const)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
@@ -38,7 +38,7 @@
 inline constexpr bool is_const_v = is_const<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_const)
+#endif // __has_builtin(__is_const)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_constructible.h b/libcxx/include/__type_traits/is_constructible.h
--- a/libcxx/include/__type_traits/is_constructible.h
+++ b/libcxx/include/__type_traits/is_constructible.h
@@ -25,7 +25,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class ..._Args>
-inline constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
+inline constexpr bool is_constructible_v = __is_constructible(_Tp, _Args...);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_convertible.h b/libcxx/include/__type_traits/is_convertible.h
--- a/libcxx/include/__type_traits/is_convertible.h
+++ b/libcxx/include/__type_traits/is_convertible.h
@@ -24,12 +24,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
+#if __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
 
 template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
     : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
 
-#else  // __has_feature(is_convertible_to)
+#else  // __has_builtin(__is_convertible_to)
 
 namespace __is_convertible_imp
 {
@@ -96,7 +96,7 @@
     static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
 };
 
-#endif // __has_feature(is_convertible_to)
+#endif // __has_builtin(__is_convertible_to)
 
 #if _LIBCPP_STD_VER > 14
 template <class _From, class _To>
diff --git a/libcxx/include/__type_traits/is_copy_assignable.h b/libcxx/include/__type_traits/is_copy_assignable.h
--- a/libcxx/include/__type_traits/is_copy_assignable.h
+++ b/libcxx/include/__type_traits/is_copy_assignable.h
@@ -13,7 +13,6 @@
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,9 +20,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
-    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
-                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
+    : public integral_constant<
+          bool,
+          __is_assignable(typename add_lvalue_reference<_Tp>::type,
+                          typename add_lvalue_reference<typename add_const<_Tp>::type>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_copy_constructible.h b/libcxx/include/__type_traits/is_copy_constructible.h
--- a/libcxx/include/__type_traits/is_copy_constructible.h
+++ b/libcxx/include/__type_traits/is_copy_constructible.h
@@ -13,7 +13,6 @@
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -23,8 +22,9 @@
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
-    : public is_constructible<_Tp,
-                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+    : public integral_constant<
+          bool,
+          __is_constructible(_Tp, typename add_lvalue_reference<typename add_const<_Tp>::type>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_default_constructible.h b/libcxx/include/__type_traits/is_default_constructible.h
--- a/libcxx/include/__type_traits/is_default_constructible.h
+++ b/libcxx/include/__type_traits/is_default_constructible.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,12 +20,12 @@
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_default_constructible
-    : public is_constructible<_Tp>
+    : public integral_constant<bool, __is_constructible(_Tp)>
     {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_default_constructible_v = is_default_constructible<_Tp>::value;
+inline constexpr bool is_default_constructible_v = __is_constructible(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_destructible.h b/libcxx/include/__type_traits/is_destructible.h
--- a/libcxx/include/__type_traits/is_destructible.h
+++ b/libcxx/include/__type_traits/is_destructible.h
@@ -22,7 +22,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_destructible)
+#if __has_builtin(__is_destructible)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
@@ -32,7 +32,7 @@
 inline constexpr bool is_destructible_v = __is_destructible(_Tp);
 #endif
 
-#else // __has_keyword(__is_destructible)
+#else // __has_builtin(__is_destructible)
 
 //  if it's a reference, return true
 //  if it's a function, return false
@@ -95,7 +95,7 @@
 inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_destructible)
+#endif // __has_builtin(__is_destructible)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_enum.h b/libcxx/include/__type_traits/is_enum.h
--- a/libcxx/include/__type_traits/is_enum.h
+++ b/libcxx/include/__type_traits/is_enum.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/remove_cv.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__type_traits/is_function.h b/libcxx/include/__type_traits/is_function.h
--- a/libcxx/include/__type_traits/is_function.h
+++ b/libcxx/include/__type_traits/is_function.h
@@ -20,7 +20,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_function)
+#if __has_builtin(__is_function)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_function : integral_constant<bool, __is_function(_Tp)> {};
@@ -31,7 +31,7 @@
 struct _LIBCPP_TEMPLATE_VIS is_function
     : public integral_constant<bool, !(is_reference<_Tp>::value || is_const<const _Tp>::value)> {};
 
-#endif // __has_keyword(__is_function)
+#endif // __has_builtin(__is_function)
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_fundamental.h b/libcxx/include/__type_traits/is_fundamental.h
--- a/libcxx/include/__type_traits/is_fundamental.h
+++ b/libcxx/include/__type_traits/is_fundamental.h
@@ -20,7 +20,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_fundamental)
+#if __has_builtin(__is_fundamental)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
@@ -30,7 +30,7 @@
 inline constexpr bool is_fundamental_v = __is_fundamental(_Tp);
 #endif
 
-#else // __has_keyword(__is_fundamental)
+#else // __has_builtin(__is_fundamental)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
     : public integral_constant<bool, is_void<_Tp>::value        ||
@@ -42,7 +42,7 @@
 inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_fundamental)
+#endif // __has_builtin(__is_fundamental)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_integral.h b/libcxx/include/__type_traits/is_integral.h
--- a/libcxx/include/__type_traits/is_integral.h
+++ b/libcxx/include/__type_traits/is_integral.h
@@ -45,7 +45,7 @@
 template <>          struct __libcpp_is_integral<__uint128_t>        { enum { value = 1 }; };
 #endif
 
-#if __has_keyword(__is_integral)
+#if __has_builtin(__is_integral)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
@@ -65,7 +65,7 @@
 inline constexpr bool is_integral_v = is_integral<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_integral)
+#endif // __has_builtin(__is_integral)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_literal_type.h b/libcxx/include/__type_traits/is_literal_type.h
--- a/libcxx/include/__type_traits/is_literal_type.h
+++ b/libcxx/include/__type_traits/is_literal_type.h
@@ -25,7 +25,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
+_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = __is_literal_type(_Tp);
 #endif // _LIBCPP_STD_VER > 14
 #endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
 
diff --git a/libcxx/include/__type_traits/is_member_function_pointer.h b/libcxx/include/__type_traits/is_member_function_pointer.h
--- a/libcxx/include/__type_traits/is_member_function_pointer.h
+++ b/libcxx/include/__type_traits/is_member_function_pointer.h
@@ -36,7 +36,7 @@
   };
 };
 
-#if __has_keyword(__is_member_function_pointer)
+#if __has_builtin(__is_member_function_pointer)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
@@ -47,7 +47,7 @@
 inline constexpr bool is_member_function_pointer_v = __is_member_function_pointer(_Tp);
 #endif
 
-#else // __has_keyword(__is_member_function_pointer)
+#else // __has_builtin(__is_member_function_pointer)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
     : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
@@ -57,7 +57,7 @@
 inline constexpr bool is_member_function_pointer_v = is_member_function_pointer<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_member_function_pointer)
+#endif // __has_builtin(__is_member_function_pointer)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_member_object_pointer.h b/libcxx/include/__type_traits/is_member_object_pointer.h
--- a/libcxx/include/__type_traits/is_member_object_pointer.h
+++ b/libcxx/include/__type_traits/is_member_object_pointer.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_member_object_pointer)
+#if __has_builtin(__is_member_object_pointer)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
@@ -29,7 +29,7 @@
 inline constexpr bool is_member_object_pointer_v = __is_member_object_pointer(_Tp);
 #endif
 
-#else // __has_keyword(__is_member_object_pointer)
+#else // __has_builtin(__is_member_object_pointer)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
     : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
@@ -39,7 +39,7 @@
 inline constexpr bool is_member_object_pointer_v = is_member_object_pointer<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_member_object_pointer)
+#endif // __has_builtin(__is_member_object_pointer)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_member_pointer.h b/libcxx/include/__type_traits/is_member_pointer.h
--- a/libcxx/include/__type_traits/is_member_pointer.h
+++ b/libcxx/include/__type_traits/is_member_pointer.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_member_pointer)
+#if __has_builtin(__is_member_pointer)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
@@ -28,7 +28,7 @@
 inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
 #endif
 
-#else // __has_keyword(__is_member_pointer)
+#else // __has_builtin(__is_member_pointer)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
  : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
@@ -38,7 +38,7 @@
 inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_member_pointer)
+#endif // __has_builtin(__is_member_pointer)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_move_assignable.h b/libcxx/include/__type_traits/is_move_assignable.h
--- a/libcxx/include/__type_traits/is_move_assignable.h
+++ b/libcxx/include/__type_traits/is_move_assignable.h
@@ -10,11 +10,9 @@
 #define _LIBCPP___TYPE_TRAITS_IS_MOVE_ASSIGNABLE_H
 
 #include <__config>
-#include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/add_rvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -22,9 +20,11 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
-    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
-                           typename add_rvalue_reference<_Tp>::type> {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_move_assignable
+    : public integral_constant<
+          bool,
+          __is_assignable(typename add_lvalue_reference<_Tp>::type, typename add_rvalue_reference<_Tp>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_move_constructible.h b/libcxx/include/__type_traits/is_move_constructible.h
--- a/libcxx/include/__type_traits/is_move_constructible.h
+++ b/libcxx/include/__type_traits/is_move_constructible.h
@@ -12,7 +12,6 @@
 #include <__config>
 #include <__type_traits/add_rvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -22,7 +21,7 @@
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_move_constructible
-    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
+    : public integral_constant<bool, __is_constructible(_Tp, typename add_rvalue_reference<_Tp>::type)>
     {};
 
 #if _LIBCPP_STD_VER > 14
diff --git a/libcxx/include/__type_traits/is_nothrow_assignable.h b/libcxx/include/__type_traits/is_nothrow_assignable.h
--- a/libcxx/include/__type_traits/is_nothrow_assignable.h
+++ b/libcxx/include/__type_traits/is_nothrow_assignable.h
@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_IS_NOTHROW_ASSIGNABLE_H
 
 #include <__config>
-#include <__type_traits/add_const.h>
 #include <__type_traits/integral_constant.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -19,39 +18,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_nothrow_assignable)
-
 template <class _Tp, class _Arg>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
     : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
 
-#else
-
-template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
-
-template <class _Tp, class _Arg>
-struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
-    : public false_type
-{
-};
-
-template <class _Tp, class _Arg>
-struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
-    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
-{
-};
-
-template <class _Tp, class _Arg>
-struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
-    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
-{
-};
-
-#endif // _LIBCPP_HAS_NO_NOEXCEPT
-
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class _Arg>
-inline constexpr bool is_nothrow_assignable_v = is_nothrow_assignable<_Tp, _Arg>::value;
+inline constexpr bool is_nothrow_assignable_v = __is_nothrow_assignable(_Tp, _Arg);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_nothrow_constructible.h b/libcxx/include/__type_traits/is_nothrow_constructible.h
--- a/libcxx/include/__type_traits/is_nothrow_constructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_constructible.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__utility/declval.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -19,55 +18,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_nothrow_constructible)
-
 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(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(_VSTD::__implicit_conversion_to<_Tp>(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 // _LIBCPP_HAS_NO_NOEXCEPT
-
-
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class ..._Args>
-inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
+inline constexpr bool is_nothrow_constructible_v = __is_nothrow_constructible(_Tp, _Args...);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_nothrow_copy_assignable.h b/libcxx/include/__type_traits/is_nothrow_copy_assignable.h
--- a/libcxx/include/__type_traits/is_nothrow_copy_assignable.h
+++ b/libcxx/include/__type_traits/is_nothrow_copy_assignable.h
@@ -13,7 +13,6 @@
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_nothrow_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,9 +20,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
-    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
-                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
+    : public integral_constant<
+          bool,
+          __is_nothrow_assignable(
+              typename add_lvalue_reference<_Tp>::type,
+              typename add_lvalue_reference<typename add_const<_Tp>::type>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_nothrow_copy_constructible.h b/libcxx/include/__type_traits/is_nothrow_copy_constructible.h
--- a/libcxx/include/__type_traits/is_nothrow_copy_constructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_copy_constructible.h
@@ -13,7 +13,6 @@
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_nothrow_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,9 +20,11 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
-    : public is_nothrow_constructible<_Tp,
-                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
+    : public integral_constant<
+          bool,
+          __is_nothrow_constructible(_Tp, typename add_lvalue_reference<typename add_const<_Tp>::type>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_nothrow_default_constructible.h b/libcxx/include/__type_traits/is_nothrow_default_constructible.h
--- a/libcxx/include/__type_traits/is_nothrow_default_constructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_default_constructible.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_nothrow_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,12 +19,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
-    : public is_nothrow_constructible<_Tp>
+    : public integral_constant<bool, __is_nothrow_constructible(_Tp)>
     {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_nothrow_default_constructible_v = is_nothrow_default_constructible<_Tp>::value;
+inline constexpr bool is_nothrow_default_constructible_v = __is_nothrow_constructible(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_nothrow_destructible.h b/libcxx/include/__type_traits/is_nothrow_destructible.h
--- a/libcxx/include/__type_traits/is_nothrow_destructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_destructible.h
@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_IS_NOTHROW_DESTRUCTIBLE_H
 
 #include <__config>
-#include <__type_traits/add_const.h>
 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_destructible.h>
 #include <__type_traits/is_reference.h>
diff --git a/libcxx/include/__type_traits/is_nothrow_move_assignable.h b/libcxx/include/__type_traits/is_nothrow_move_assignable.h
--- a/libcxx/include/__type_traits/is_nothrow_move_assignable.h
+++ b/libcxx/include/__type_traits/is_nothrow_move_assignable.h
@@ -13,7 +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_nothrow_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,10 +20,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
-    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
-                                     typename add_rvalue_reference<_Tp>::type>
-    {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
+    : public integral_constant<
+          bool,
+          __is_nothrow_assignable(typename add_lvalue_reference<_Tp>::type, typename add_rvalue_reference<_Tp>::type)> {
+};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_nothrow_move_constructible.h b/libcxx/include/__type_traits/is_nothrow_move_constructible.h
--- a/libcxx/include/__type_traits/is_nothrow_move_constructible.h
+++ b/libcxx/include/__type_traits/is_nothrow_move_constructible.h
@@ -21,7 +21,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
-    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
+    : public integral_constant<bool, __is_nothrow_constructible(_Tp, typename add_rvalue_reference<_Tp>::type)>
     {};
 
 #if _LIBCPP_STD_VER > 14
diff --git a/libcxx/include/__type_traits/is_object.h b/libcxx/include/__type_traits/is_object.h
--- a/libcxx/include/__type_traits/is_object.h
+++ b/libcxx/include/__type_traits/is_object.h
@@ -22,7 +22,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_object)
+#if __has_builtin(__is_object)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
@@ -32,7 +32,7 @@
 inline constexpr bool is_object_v = __is_object(_Tp);
 #endif
 
-#else // __has_keyword(__is_object)
+#else // __has_builtin(__is_object)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
     : public integral_constant<bool, is_scalar<_Tp>::value ||
@@ -45,7 +45,7 @@
 inline constexpr bool is_object_v = is_object<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_object)
+#endif // __has_builtin(__is_object)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_pod.h b/libcxx/include/__type_traits/is_pod.h
--- a/libcxx/include/__type_traits/is_pod.h
+++ b/libcxx/include/__type_traits/is_pod.h
@@ -18,24 +18,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
-
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
     : public integral_constant<bool, __is_pod(_Tp)> {};
 
-#else
-
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
-    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
-                                     is_trivially_copy_constructible<_Tp>::value      &&
-                                     is_trivially_copy_assignable<_Tp>::value    &&
-                                     is_trivially_destructible<_Tp>::value> {};
-
-#endif
-
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_pod_v = is_pod<_Tp>::value;
+inline constexpr bool is_pod_v = __is_pod(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_pointer.h b/libcxx/include/__type_traits/is_pointer.h
--- a/libcxx/include/__type_traits/is_pointer.h
+++ b/libcxx/include/__type_traits/is_pointer.h
@@ -19,7 +19,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_pointer)
+#if __has_builtin(__is_pointer)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
@@ -29,7 +29,7 @@
 inline constexpr bool is_pointer_v = __is_pointer(_Tp);
 #endif
 
-#else // __has_keyword(__is_pointer)
+#else // __has_builtin(__is_pointer)
 
 template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
 template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
@@ -50,7 +50,7 @@
 inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_pointer)
+#endif // __has_builtin(__is_pointer)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_reference.h b/libcxx/include/__type_traits/is_reference.h
--- a/libcxx/include/__type_traits/is_reference.h
+++ b/libcxx/include/__type_traits/is_reference.h
@@ -18,9 +18,9 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_lvalue_reference) && \
-    __has_keyword(__is_rvalue_reference) && \
-    __has_keyword(__is_reference)
+#if __has_builtin(__is_lvalue_reference) && \
+    __has_builtin(__is_rvalue_reference) && \
+    __has_builtin(__is_reference)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
@@ -40,7 +40,7 @@
 inline constexpr bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
 #endif
 
-#else // __has_keyword(__is_lvalue_reference) && etc...
+#else // __has_builtin(__is_lvalue_reference) && etc...
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
@@ -63,7 +63,7 @@
 inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_lvalue_reference) && etc...
+#endif // __has_builtin(__is_lvalue_reference) && etc...
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_scalar.h b/libcxx/include/__type_traits/is_scalar.h
--- a/libcxx/include/__type_traits/is_scalar.h
+++ b/libcxx/include/__type_traits/is_scalar.h
@@ -22,7 +22,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_scalar)
+#if __has_builtin(__is_scalar)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
@@ -32,7 +32,7 @@
 inline constexpr bool is_scalar_v = __is_scalar(_Tp);
 #endif
 
-#else // __has_keyword(__is_scalar)
+#else // __has_builtin(__is_scalar)
 
 template <class _Tp> struct __is_block : false_type {};
 #if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
@@ -54,7 +54,7 @@
 inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_scalar)
+#endif // __has_builtin(__is_scalar)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_signed.h b/libcxx/include/__type_traits/is_signed.h
--- a/libcxx/include/__type_traits/is_signed.h
+++ b/libcxx/include/__type_traits/is_signed.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_signed)
+#if __has_builtin(__is_signed)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
@@ -28,7 +28,7 @@
 inline constexpr bool is_signed_v = __is_signed(_Tp);
 #endif
 
-#else // __has_keyword(__is_signed)
+#else // __has_builtin(__is_signed)
 
 template <class _Tp, bool = is_integral<_Tp>::value>
 struct __libcpp_is_signed_impl : public _BoolConstant<(_Tp(-1) < _Tp(0))> {};
@@ -48,7 +48,7 @@
 inline constexpr bool is_signed_v = is_signed<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_signed)
+#endif // __has_builtin(__is_signed)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_standard_layout.h b/libcxx/include/__type_traits/is_standard_layout.h
--- a/libcxx/include/__type_traits/is_standard_layout.h
+++ b/libcxx/include/__type_traits/is_standard_layout.h
@@ -19,16 +19,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
-#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
     : public integral_constant<bool, __is_standard_layout(_Tp)>
-#else
-    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
-#endif
     {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
+inline constexpr bool is_standard_layout_v = __is_standard_layout(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivial.h b/libcxx/include/__type_traits/is_trivial.h
--- a/libcxx/include/__type_traits/is_trivial.h
+++ b/libcxx/include/__type_traits/is_trivial.h
@@ -19,17 +19,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
-#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
     : public integral_constant<bool, __is_trivial(_Tp)>
-#else
-    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
-                                 is_trivially_default_constructible<_Tp>::value>
-#endif
     {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
+inline constexpr bool is_trivial_v = __is_trivial(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivially_assignable.h b/libcxx/include/__type_traits/is_trivially_assignable.h
--- a/libcxx/include/__type_traits/is_trivially_assignable.h
+++ b/libcxx/include/__type_traits/is_trivially_assignable.h
@@ -25,7 +25,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class _Arg>
-inline constexpr bool is_trivially_assignable_v = is_trivially_assignable<_Tp, _Arg>::value;
+inline constexpr bool is_trivially_assignable_v = __is_trivially_assignable(_Tp, _Arg);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivially_constructible.h b/libcxx/include/__type_traits/is_trivially_constructible.h
--- a/libcxx/include/__type_traits/is_trivially_constructible.h
+++ b/libcxx/include/__type_traits/is_trivially_constructible.h
@@ -26,7 +26,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class... _Args>
-inline constexpr bool is_trivially_constructible_v = is_trivially_constructible<_Tp, _Args...>::value;
+inline constexpr bool is_trivially_constructible_v = __is_trivially_constructible(_Tp, _Args...);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivially_copy_assignable.h b/libcxx/include/__type_traits/is_trivially_copy_assignable.h
--- a/libcxx/include/__type_traits/is_trivially_copy_assignable.h
+++ b/libcxx/include/__type_traits/is_trivially_copy_assignable.h
@@ -13,7 +13,6 @@
 #include <__type_traits/add_const.h>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_trivially_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,9 +20,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
-    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
-                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
+    : public integral_constant<
+          bool,
+          __is_trivially_assignable(
+              typename add_lvalue_reference<_Tp>::type,
+              typename add_lvalue_reference<typename add_const<_Tp>::type>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_trivially_copy_constructible.h b/libcxx/include/__type_traits/is_trivially_copy_constructible.h
--- a/libcxx/include/__type_traits/is_trivially_copy_constructible.h
+++ b/libcxx/include/__type_traits/is_trivially_copy_constructible.h
@@ -12,7 +12,6 @@
 #include <__config>
 #include <__type_traits/add_lvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_trivially_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,7 +20,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
-    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
+    : public integral_constant<bool, __is_trivially_constructible(_Tp, typename add_lvalue_reference<const _Tp>::type)>
     {};
 
 #if _LIBCPP_STD_VER > 14
diff --git a/libcxx/include/__type_traits/is_trivially_copyable.h b/libcxx/include/__type_traits/is_trivially_copyable.h
--- a/libcxx/include/__type_traits/is_trivially_copyable.h
+++ b/libcxx/include/__type_traits/is_trivially_copyable.h
@@ -24,7 +24,7 @@
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
+inline constexpr bool is_trivially_copyable_v = __is_trivially_copyable(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivially_default_constructible.h b/libcxx/include/__type_traits/is_trivially_default_constructible.h
--- a/libcxx/include/__type_traits/is_trivially_default_constructible.h
+++ b/libcxx/include/__type_traits/is_trivially_default_constructible.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_trivially_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,12 +19,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
-    : public is_trivially_constructible<_Tp>
+    : public integral_constant<bool, __is_trivially_constructible(_Tp)>
     {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
-inline constexpr bool is_trivially_default_constructible_v = is_trivially_default_constructible<_Tp>::value;
+inline constexpr bool is_trivially_default_constructible_v = __is_trivially_constructible(_Tp);
 #endif
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/is_trivially_destructible.h b/libcxx/include/__type_traits/is_trivially_destructible.h
--- a/libcxx/include/__type_traits/is_trivially_destructible.h
+++ b/libcxx/include/__type_traits/is_trivially_destructible.h
@@ -18,29 +18,21 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_trivially_destructible)
+#if __has_builtin(__is_trivially_destructible)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
     : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
 
-#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
+#elif __has_builtin(__has_trivial_destructor)
 
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
     : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
 
 #else
 
-template <class _Tp> struct __libcpp_trivial_destructor
-    : public integral_constant<bool, is_scalar<_Tp>::value ||
-                                     is_reference<_Tp>::value> {};
+#error is_trivially_destructible isn't implemented
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
-    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
-
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
-    : public false_type {};
-
-#endif
+#endif // __has_builtin(__is_trivially_destructible)
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_trivially_move_assignable.h b/libcxx/include/__type_traits/is_trivially_move_assignable.h
--- a/libcxx/include/__type_traits/is_trivially_move_assignable.h
+++ b/libcxx/include/__type_traits/is_trivially_move_assignable.h
@@ -13,7 +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_trivially_assignable.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,10 +20,12 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
-    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
-                                     typename add_rvalue_reference<_Tp>::type>
-    {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
+    : public integral_constant<
+          bool,
+          __is_trivially_assignable(
+              typename add_lvalue_reference<_Tp>::type, typename add_rvalue_reference<_Tp>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_trivially_move_constructible.h b/libcxx/include/__type_traits/is_trivially_move_constructible.h
--- a/libcxx/include/__type_traits/is_trivially_move_constructible.h
+++ b/libcxx/include/__type_traits/is_trivially_move_constructible.h
@@ -12,7 +12,6 @@
 #include <__config>
 #include <__type_traits/add_rvalue_reference.h>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_trivially_constructible.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,9 +19,9 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
-    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
-    {};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
+    : public integral_constant<bool, __is_trivially_constructible(_Tp, typename add_rvalue_reference<_Tp>::type)> {};
 
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
diff --git a/libcxx/include/__type_traits/is_union.h b/libcxx/include/__type_traits/is_union.h
--- a/libcxx/include/__type_traits/is_union.h
+++ b/libcxx/include/__type_traits/is_union.h
@@ -11,7 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/remove_cv.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__type_traits/is_unsigned.h b/libcxx/include/__type_traits/is_unsigned.h
--- a/libcxx/include/__type_traits/is_unsigned.h
+++ b/libcxx/include/__type_traits/is_unsigned.h
@@ -21,7 +21,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 // Before AppleClang 14, __is_unsigned returned true for enums with signed underlying type.
-#if __has_keyword(__is_unsigned) && !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1400)
+#if __has_builtin(__is_unsigned) && !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1400)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
@@ -31,7 +31,7 @@
 inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
 #endif
 
-#else // __has_keyword(__is_unsigned)
+#else // __has_builtin(__is_unsigned)
 
 template <class _Tp, bool = is_integral<_Tp>::value>
 struct __libcpp_is_unsigned_impl : public _BoolConstant<(_Tp(0) < _Tp(-1))> {};
@@ -51,7 +51,7 @@
 inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_unsigned)
+#endif // __has_builtin(__is_unsigned)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_void.h b/libcxx/include/__type_traits/is_void.h
--- a/libcxx/include/__type_traits/is_void.h
+++ b/libcxx/include/__type_traits/is_void.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_void)
+#if __has_builtin(__is_void)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
@@ -38,7 +38,7 @@
 inline constexpr bool is_void_v = is_void<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_void)
+#endif // __has_builtin(__is_void)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/is_volatile.h b/libcxx/include/__type_traits/is_volatile.h
--- a/libcxx/include/__type_traits/is_volatile.h
+++ b/libcxx/include/__type_traits/is_volatile.h
@@ -18,7 +18,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_keyword(__is_volatile)
+#if __has_builtin(__is_volatile)
 
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
@@ -38,7 +38,7 @@
 inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
 #endif
 
-#endif // __has_keyword(__is_volatile)
+#endif // __has_builtin(__is_volatile)
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxx/include/__type_traits/negation.h b/libcxx/include/__type_traits/negation.h
--- a/libcxx/include/__type_traits/negation.h
+++ b/libcxx/include/__type_traits/negation.h
@@ -25,7 +25,7 @@
 template <class _Tp>
 struct negation : _Not<_Tp> {};
 template<class _Tp>
-inline constexpr bool negation_v = negation<_Tp>::value;
+inline constexpr bool negation_v = !_Tp::value;
 #endif // _LIBCPP_STD_VER > 14
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__type_traits/rank.h b/libcxx/include/__type_traits/rank.h
--- a/libcxx/include/__type_traits/rank.h
+++ b/libcxx/include/__type_traits/rank.h
@@ -19,6 +19,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if __has_builtin(__array_rank)
+
+template <class _Tp>
+struct rank : integral_constant<size_t, __array_rank(_Tp)> {};
+
+#else
+
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
     : public integral_constant<size_t, 0> {};
 template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
@@ -26,6 +33,8 @@
 template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
     : public integral_constant<size_t, rank<_Tp>::value + 1> {};
 
+#endif // __has_builtin(__array_rank)
+
 #if _LIBCPP_STD_VER > 14
 template <class _Tp>
 inline constexpr size_t rank_v = rank<_Tp>::value;