1 files changed, 1 insertions, 1 deletions

diff --git a/parse.y b/parse.y
index 64a70d7de4..52d0f2a139 100644
--- a/parse.y
+++ b/parse.y
@@ -4947,7 +4947,7 @@ arg_prepend(node1, node2)
 	return node2;
 
       default:
-	rb_bug("unknown nodetype(%d) for arg_prepend");
+	rb_bug("unknown nodetype(%d) for arg_prepend", nodetype(node2));
     }
     return 0;			/* not reached */
 }