diff --git a/Reflection/tagged_ctor_arg.h b/Reflection/tagged_ctor_arg.h
index c4b3388..e868fe2 100644
--- a/Reflection/tagged_ctor_arg.h
+++ b/Reflection/tagged_ctor_arg.h
@@ -64,11 +64,17 @@ namespace Alepha::Hydrogen::Reflection  ::detail::  tagged_ctor_arg_m
 		template< typename Forbidden >
 		struct argument
 		{
-			template< typename T, typename= std::enable_if_t< not std::is_same_v< T, Forbidden > > >
+			template< typename T >
+			requires( not Concepts::SameAs< T, Forbidden > )
 			constexpr operator T ();
 		};
 
-		template< typename T, typename ... Args, typename= std::enable_if_t< std::is_constructible_v< T, Args... > > >
+		template< typename T, typename ... Args >
+		requires( Concepts::ConstructibleFrom< T, Args... > )
+		constexpr void construct( const std::tuple< Args... > & );
+
+		template< typename T, typename ... Args >
+		requires( Concepts::ConstructibleFrom< T, Args... > )
 		constexpr void construct( std::tuple< Args... > && );
 
 		template