Fix a bug in the parser found by inspection
diff --git a/src/bc/parse.c b/src/bc/parse.c
index 2373de4..85b6394 100644
--- a/src/bc/parse.c
+++ b/src/bc/parse.c
@@ -2657,6 +2657,7 @@
     ip = bc_vec_item(&parse->exit_labels, top);
 
     while (top < parse->exit_labels.len && ip && !ip->func) {
+      ip = bc_vec_item(&parse->exit_labels, top);
       --top;
     }