[libc++] Replace __libcpp_is_final with a variable template (#167137)

Author: philnik777

libcxx/include/__exception/nested_exception.h

@@ -73,7 +73,7 @@ template <class _Tp>
   __throw_with_nested<_Tp,
                       _Up,
                       is_class<_Up>::value && !is_base_of<nested_exception, _Up>::value &&
-                          !__libcpp_is_final<_Up>::value>::__do_throw(std::forward<_Tp>(__t));
+                          !__is_final_v<_Up> >::__do_throw(std::forward<_Tp>(__t));
 #else
   ((void)__t);
   // FIXME: Make this abort

libcxx/include/__memory/compressed_pair.h

@@ -67,7 +67,7 @@ inline const size_t __compressed_pair_alignment<_Tp&> = _LIBCPP_ALIGNOF(void*);
 
 template <class _ToPad>
 inline const bool __is_reference_or_unpadded_object =
-    (is_empty<_ToPad>::value && !__libcpp_is_final<_ToPad>::value) || sizeof(_ToPad) == __datasizeof_v<_ToPad>;
+    (is_empty<_ToPad>::value && !__is_final_v<_ToPad>) || sizeof(_ToPad) == __datasizeof_v<_ToPad>;
 
 template <class _Tp>
 inline const bool __is_reference_or_unpadded_object<_Tp&> = true;

libcxx/include/__type_traits/is_final.h

@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-struct __libcpp_is_final : integral_constant<bool, __is_final(_Tp)> {};
+inline const bool __is_final_v = __is_final(_Tp);
 
 #if _LIBCPP_STD_VER >= 14
 template <class _Tp>

libcxx/include/tuple

@@ -347,7 +347,7 @@ using __tuple_common_comparison_category _LIBCPP_NODEBUG =
 
 // __tuple_leaf
 
-template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value >
+template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__is_final_v<_Hp> >
 class __tuple_leaf;
 
 template <size_t _Ip, class _Hp, bool _Ep>

libcxx/test/libcxx/utilities/memory/util.smartptr/util.smartptr.shared/libcxx.control_block_layout.pass.cpp

@@ -30,7 +30,7 @@
 
 struct value_init_tag {};
 
-template <class T, int _Idx, bool CanBeEmptyBase = std::is_empty<T>::value && !std::__libcpp_is_final<T>::value>
+template <class T, int _Idx, bool CanBeEmptyBase = std::is_empty<T>::value && !std::__is_final_v<T>>
 struct compressed_pair_elem {
   explicit compressed_pair_elem(value_init_tag) : value_() {}