diff -r bfbe4aca6b77 -r 9b61eb4f00dc stage4/generate_c/generate_c_typedecl.cc
--- a/stage4/generate_c/generate_c_typedecl.cc	Tue Nov 13 18:02:15 2012 +0000
+++ b/stage4/generate_c/generate_c_typedecl.cc	Tue Nov 13 18:03:17 2012 +0000
@@ -317,7 +317,10 @@
   if (current_typedefinition == enumerated_td)
     current_type_name->accept(*basedecl);
   else {
-    if (NULL == symbol->datatype) ERROR;
+    if (NULL == symbol->datatype) {
+      debug_c::print(symbol);
+      ERROR;
+    }
     symbol->datatype->accept(*basedecl);
   }
   s4o_incl.print("__");