diff --git a/src/proto/gc.pro b/src/proto/gc.pro
index 8b55030..8c8f73f 100644
--- a/src/proto/gc.pro
+++ b/src/proto/gc.pro
@@ -5,6 +5,7 @@
 int set_ref_in_dict(dict_T *d, int copyID);
 int set_ref_in_list(list_T *ll, int copyID);
 int set_ref_in_list_items(list_T *l, int copyID, ht_stack_T **ht_stack, tuple_stack_T **tuple_stack);
+int set_ref_in_tuple(tuple_T *tuple, int copyID);
 int set_ref_in_tuple_items(tuple_T *tuple, int copyID, ht_stack_T **ht_stack, list_stack_T **list_stack);
 int set_ref_in_callback(callback_T *cb, int copyID);
 int set_ref_in_item_class(class_T *cl, int copyID, ht_stack_T **ht_stack, list_stack_T **list_stack, tuple_stack_T **tuple_stack);