--- a/stage4/generate_iec/generate_iec.cc	Thu Mar 01 10:28:27 2012 +0000
+++ b/stage4/generate_iec/generate_iec.cc	Fri Mar 02 12:53:41 2012 +0000
@@ -58,6 +58,10 @@
 
 
 
+#define ERROR error_exit(__FILE__,__LINE__)
+/* function defined in main.cc */
+extern void error_exit(const char *file_name, int line_no);
+
 
 
 
@@ -153,6 +157,13 @@
 #endif
 
 
+/* A class used to identify an entry (literal, variable, etc...) in the abstract syntax tree with an invalid data type */
+/* This is only used from stage3 onwards. Stages 1 and 2 will never create any instances of invalid_type_name_c */
+// SYM_REF0(invalid_type_name_c)
+void *visit(invalid_type_name_c *symbol) {
+  ERROR;
+  return NULL;
+}
 
 
 /******************/