diff -r 3d682f87c870 -r dea39ef02847 stage3/fill_candidate_datatypes.hh
--- a/stage3/fill_candidate_datatypes.hh	Mon Feb 24 22:00:55 2014 +0000
+++ b/stage3/fill_candidate_datatypes.hh	Sun Mar 02 16:42:56 2014 +0000
@@ -327,6 +327,7 @@
     /***********************/
     /* B 3.1 - Expressions */
     /***********************/
+    void *visit(ref_expression_c *symbol);
     void *visit(or_expression_c *symbol);
     void *visit(xor_expression_c *symbol);
     void *visit(and_expression_c *symbol);