--- a/plcopen/structures.py	Tue Sep 01 16:58:03 2009 +0200
+++ b/plcopen/structures.py	Tue Sep 01 16:59:37 2009 +0200
@@ -469,6 +469,8 @@
         outs = reduce(lambda a,b: a or b, map(lambda testtype : IsOfType(fdecl["outputs"][0][1],testtype), OutTypes))
         inps = reduce(lambda a,b: a or b, map(lambda testtype : IsOfType(fdecl["inputs"][0][1],testtype), InTypes))
         if inps and outs and fdecl["outputs"][0][1] != fdecl["inputs"][0][1]:
+             if Format[1] is None:
+                 return (Format[0], "__move_", "IN_type")
              return Format
     
     return None