#if _LIBCPP_STD_VER > 14
template <class _Tp>
-inline constexpr bool is_abstract_v = __is_abstract(_Tp);
+inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
template <class _Tp>
-inline constexpr bool is_aggregate_v = __is_aggregate(_Tp);
+inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
#endif // _LIBCPP_STD_VER > 14
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_arithmetic)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_arithmetic : integral_constant<bool, __is_arithmetic(_Tp)> {};
-
-#else
-
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
: public integral_constant<bool, is_integral<_Tp>::value ||
is_floating_point<_Tp>::value> {};
-#endif // __has_keyword(__is_arithmetic)
-
#if _LIBCPP_STD_VER > 14
template <class _Tp>
inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
#if _LIBCPP_STD_VER > 14
template <class _Bp, class _Dp>
-inline constexpr bool is_base_of_v = __is_base_of(_Bp, _Dp);
+inline constexpr bool is_base_of_v = is_base_of<_Bp, _Dp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_BEGIN_NAMESPACE_STD
+#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
+
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
: public integral_constant<bool, __is_class(_Tp)> {};
+#else
+
+namespace __is_class_imp
+{
+template <class _Tp> true_type __test(int _Tp::*);
+template <class _Tp> false_type __test(...);
+}
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
+ : public integral_constant<bool, decltype(__is_class_imp::__test<_Tp>(0))::value && !is_union<_Tp>::value> {};
+
+#endif
+
#if _LIBCPP_STD_VER > 14
template <class _Tp>
-inline constexpr bool is_class_v = __is_class(_Tp);
+inline constexpr bool is_class_v = is_class<_Tp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_compound)
+// >= 11 because in C++03 nullptr isn't actually nullptr
+#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG)
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
_LIBCPP_BEGIN_NAMESPACE_STD
+#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
+
template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_empty
: public integral_constant<bool, __is_empty(_Tp)> {};
+#else // __has_feature(is_empty)
+
+template <class _Tp>
+struct __is_empty1
+ : public _Tp
+{
+ double __lx;
+};
+
+struct __is_empty2
+{
+ double __lx;
+};
+
+template <class _Tp, bool = is_class<_Tp>::value>
+struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
+
+template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
+
+#endif // __has_feature(is_empty)
+
#if _LIBCPP_STD_VER > 14
template <class _Tp>
-inline constexpr bool is_empty_v = __is_empty(_Tp);
+inline constexpr bool is_empty_v = is_empty<_Tp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_BEGIN_NAMESPACE_STD
+#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
+
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
: public integral_constant<bool, __is_enum(_Tp)> {};
inline constexpr bool is_enum_v = __is_enum(_Tp);
#endif
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
+ : public integral_constant<bool, !is_void<_Tp>::value &&
+ !is_integral<_Tp>::value &&
+ !is_floating_point<_Tp>::value &&
+ !is_array<_Tp>::value &&
+ !is_pointer<_Tp>::value &&
+ !is_reference<_Tp>::value &&
+ !is_member_pointer<_Tp>::value &&
+ !is_union<_Tp>::value &&
+ !is_class<_Tp>::value &&
+ !is_function<_Tp>::value > {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_enum_v = is_enum<_Tp>::value;
+#endif
+
+#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
+
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___TYPE_TRAITS_IS_ENUM_H
#if _LIBCPP_STD_VER > 14
template <class _Tp>
-inline constexpr bool is_final_v = __is_final(_Tp);
+inline constexpr bool is_final_v = is_final<_Tp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_floating_point)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_floating_point : integral_constant<bool, __is_floating_point(_Tp)> {};
-
-#else
-
template <class _Tp> struct __libcpp_is_floating_point : public false_type {};
template <> struct __libcpp_is_floating_point<float> : public true_type {};
template <> struct __libcpp_is_floating_point<double> : public true_type {};
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
: public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
-#endif // __has_keyword(__is_floating_point)
-
#if _LIBCPP_STD_VER > 14
template <class _Tp>
inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_function)
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_function : integral_constant<bool, __is_function(_Tp)> {};
-
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
+ : public _BoolConstant<
+#ifdef __clang__
+ __is_function(_Tp)
#else
+ !(is_reference<_Tp>::value || is_const<const _Tp>::value)
+#endif
+ > {};
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_function
- : public integral_constant<bool, !(is_reference<_Tp>::value || is_const<const _Tp>::value)> {};
-
-#endif // __has_keyword(__is_function)
#if _LIBCPP_STD_VER > 14
template <class _Tp>
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_fundamental)
+// Before Clang 10, __is_fundamental didn't work for nullptr_t.
+// In C++03 nullptr_t is library-provided but must still count as "fundamental."
+#if __has_keyword(__is_fundamental) && \
+ !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) && \
+ !defined(_LIBCPP_CXX03_LANG)
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_pointer)
+// Before AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
+#if __has_keyword(__is_pointer) && \
+ !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_keyword(__is_scalar)
+// In C++03 nullptr_t is library-provided but must still count as "scalar."
+#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG)
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
_LIBCPP_BEGIN_NAMESPACE_STD
+#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
+
template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
: public integral_constant<bool, __is_union(_Tp)> {};
+#else
+
+template <class _Tp> struct __libcpp_union : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
+ : public __libcpp_union<typename remove_cv<_Tp>::type> {};
+
+#endif
+
#if _LIBCPP_STD_VER > 14
template <class _Tp>
-inline constexpr bool is_union_v = __is_union(_Tp);
+inline constexpr bool is_union_v = is_union<_Tp>::value;
#endif
_LIBCPP_END_NAMESPACE_STD
_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)
+// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
+// No currently-released version of AppleClang contains the fixed intrinsic.
+#if __has_keyword(__is_unsigned) && \
+ !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) && \
+ !defined(_LIBCPP_APPLE_CLANG_VER)
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };