diff --git a/source/dyaml/representer.d b/source/dyaml/representer.d
index f90f7f4..6a88ee5 100644
--- a/source/dyaml/representer.d
+++ b/source/dyaml/representer.d
@@ -224,10 +224,11 @@ final class Representer
          * }
          * --------------------
          */
-        void addRepresenter(T)(Node function(ref Node, Representer) representer) @trusted
+        void addRepresenter(T)(Node function(ref Node, Representer) representer) 
+            @trusted pure
         {
             assert((typeid(T) in representers_) is null, 
-                   "Representer function for data type " ~ typeid(T).toString() ~
+                   "Representer function for data type " ~ T.stringof ~
                    " already specified. Can't specify another one");
             representers_[typeid(T)] = representer;
         }