component_traits: refine internal checks

src/entt/entity/component.hpp

@@ -1,6 +1,7 @@
 #ifndef ENTT_ENTITY_COMPONENT_HPP
 #define ENTT_ENTITY_COMPONENT_HPP
 
+#include <concepts>
 #include <cstddef>
 #include <type_traits>
 #include "../config/config.h"
@@ -11,25 +12,25 @@ namespace entt {
 /*! @cond ENTT_INTERNAL */
 namespace internal {
 
-template<typename Type, typename = void>
+template<typename Type>
 struct in_place_delete: std::bool_constant<!(std::is_move_constructible_v<Type> && std::is_move_assignable_v<Type>)> {};
 
 template<>
 struct in_place_delete<void>: std::false_type {};
 
 template<typename Type>
-struct in_place_delete<Type, std::enable_if_t<Type::in_place_delete>>
-    : std::true_type {};
+requires Type::in_place_delete
+struct in_place_delete<Type>: std::true_type {};
 
-template<typename Type, typename = void>
+template<typename Type>
 struct page_size: std::integral_constant<std::size_t, !std::is_empty_v<ENTT_ETO_TYPE(Type)> * ENTT_PACKED_PAGE> {};
 
 template<>
 struct page_size<void>: std::integral_constant<std::size_t, 0u> {};
 
 template<typename Type>
-struct page_size<Type, std::void_t<decltype(Type::page_size)>>
-    : std::integral_constant<std::size_t, Type::page_size> {};
+requires std::is_convertible_v<decltype(Type::page_size), std::size_t>
+struct page_size<Type>: std::integral_constant<std::size_t, Type::page_size> {};
 
 } // namespace internal
 /*! @endcond */