diff --git a/tools/mrbc/mrbc.c b/tools/mrbc/mrbc.c
index 46d0d95ca..e2179d708 100644
--- a/tools/mrbc/mrbc.c
+++ b/tools/mrbc/mrbc.c
@@ -11,7 +11,6 @@
 
 void mrb_show_version(mrb_state *);
 void mrb_show_copyright(mrb_state *);
-void parser_dump(mrb_state*, struct mrb_ast_node*, int);
 
 struct mrbc_args {
   int argc;