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/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_builtin(__has_virtual_destructor)
-
 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_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_builtin(__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_builtin(__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_builtin(__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_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_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_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_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_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_builtin(__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 // __has_builtin(__is_nothrow_assignable)
-
 #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_builtin(__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 // __has_builtin(__is_nothrow_constructible)
-
-
 #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_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_builtin(__is_pod)
-
 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 // __has_builtin(__is_pod)
-
 #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_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_builtin(__is_standard_layout)
     : 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_builtin(__is_trivial)
     : 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
@@ -30,15 +30,7 @@
 
 #else
 
-template <class _Tp> struct __libcpp_trivial_destructor
-    : public integral_constant<bool, is_scalar<_Tp>::value ||
-                                     is_reference<_Tp>::value> {};
-
-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 {};
+#error is_trivially_destructible is not implemented
 
 #endif // __has_builtin(__is_trivially_destructible)
 
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/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 +19,14 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+// TODO: Enable using the builtin __array_rank when https://llvm.org/PR57133 is resolved
+#if __has_builtin(__array_rank) && 0
+
+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 +34,8 @@
 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;