diff --git a/src/lib/meta/typelist.hpp b/src/lib/meta/typelist.hpp
index d0cbb44f3..53474572e 100644
--- a/src/lib/meta/typelist.hpp
+++ b/src/lib/meta/typelist.hpp
@@ -85,6 +85,10 @@ namespace meta {
         typedef T Tail;
       };
     
+    typedef Node<NullType,NullType> NodeNull;
+    
+    
+    
     template
       < class T01=NullType
       , class T02=NullType
@@ -115,19 +119,18 @@ namespace meta {
                               , T13, T14, T15, T16
                               , T17, T18, T19, T20>::List ListTail;
       public:
-        typedef Node<T01, ListTail> List;
+        using List = Node<T01, ListTail>;
+        using Seq  = Types;
       };
     
     template<> 
     struct Types<>
       {
-        typedef NullType List;
-        typedef Types<>  Seq;
+        using List = NullType;
+        using Seq  = Types<>;
       };
     
     
-    typedef Node<NullType,NullType> NodeNull;
-    
     
 }} // namespace lib::meta
 #endif