diff --git a/src/mem/slicc/ast/TypeFieldMemberAST.py b/src/mem/slicc/ast/TypeFieldMemberAST.py
--- a/src/mem/slicc/ast/TypeFieldMemberAST.py
+++ b/src/mem/slicc/ast/TypeFieldMemberAST.py
@@ -54,4 +54,4 @@
         if not type.addDataMember(self.field_id, field_type, self.pairs,
                                   init_code):
 
-            self.error("Duplicate data member: %s:%s" % (type_ptr, field_id))
+            self.error("Duplicate data member: %s:%s" % (self.type_ast, self.field_id))