[libc++] Simplify is_array and is_nothrow_convertible

Author: philnik777

libcxx/include/CMakeLists.txt

@@ -829,7 +829,6 @@ set(files
   __type_traits/is_member_pointer.h
   __type_traits/is_nothrow_assignable.h
   __type_traits/is_nothrow_constructible.h
-  __type_traits/is_nothrow_convertible.h
   __type_traits/is_nothrow_destructible.h
   __type_traits/is_null_pointer.h
   __type_traits/is_object.h

libcxx/include/__type_traits/is_array.h

@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_IS_ARRAY_H
 
 #include <__config>
-#include <__cstddef/size_t.h>
 #include <__type_traits/integral_constant.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -19,32 +18,13 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_array) &&                                                                                       \
-    (!defined(_LIBCPP_COMPILER_CLANG_BASED) || (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1900))
-
 template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_array : _BoolConstant<__is_array(_Tp)> {};
 
-#  if _LIBCPP_STD_VER >= 17
+#if _LIBCPP_STD_VER >= 17
 template <class _Tp>
 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_array_v = __is_array(_Tp);
-#  endif
-
-#else
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_array : public false_type {};
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]> : public true_type {};
-template <class _Tp, size_t _Np>
-struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]> : public true_type {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_array_v = is_array<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_array)
+#endif
 
 _LIBCPP_END_NAMESPACE_STD
 

libcxx/include/__type_traits/is_convertible.h

@@ -27,6 +27,16 @@ template <class _From, class _To>
 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_convertible_v = __is_convertible(_From, _To);
 #endif
 
+#if _LIBCPP_STD_VER >= 20
+
+template <class _Tp, class _Up>
+struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_convertible : bool_constant<__is_nothrow_convertible(_Tp, _Up)> {};
+
+template <class _Tp, class _Up>
+_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_convertible_v = __is_nothrow_convertible(_Tp, _Up);
+
+#endif // _LIBCPP_STD_VER >= 20
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_CONVERTIBLE_H

libcxx/include/__type_traits/is_nothrow_convertible.h

@@ -231,10 +231,6 @@ module std_core [system] {
       header "__type_traits/is_nothrow_constructible.h"
       export std_core.type_traits.integral_constant
     }
-    module is_nothrow_convertible {
-      header "__type_traits/is_nothrow_convertible.h"
-      export std_core.type_traits.integral_constant
-    }
     module is_nothrow_destructible {
       header "__type_traits/is_nothrow_destructible.h"
       export std_core.type_traits.integral_constant

libcxx/include/module.modulemap

@@ -549,7 +549,6 @@ namespace std
 #    include <__type_traits/common_reference.h>
 #    include <__type_traits/is_bounded_array.h>
 #    include <__type_traits/is_constant_evaluated.h>
-#    include <__type_traits/is_nothrow_convertible.h>
 #    include <__type_traits/is_unbounded_array.h>
 #    include <__type_traits/type_identity.h>
 #    include <__type_traits/unwrap_ref.h>