diff --git a/submodule.c b/submodule.c
index d3299e29c0..be0f5d8478 100644
--- a/submodule.c
+++ b/submodule.c
@@ -951,17 +951,18 @@ static void submodule_collect_changed_cb(struct diff_queue_struct *q,
 	}
 }
 
-static int add_sha1_to_array(const char *ref, const struct object_id *oid,
-			     int flags, void *data)
+static int append_oid_to_array(const char *ref, const struct object_id *oid,
+			       int flags, void *data)
 {
-	oid_array_append(data, oid);
+	struct oid_array *array = data;
+	oid_array_append(array, oid);
 	return 0;
 }
 
 void check_for_new_submodule_commits(struct object_id *oid)
 {
 	if (!initialized_fetch_ref_tips) {
-		for_each_ref(add_sha1_to_array, &ref_tips_before_fetch);
+		for_each_ref(append_oid_to_array, &ref_tips_before_fetch);
 		initialized_fetch_ref_tips = 1;
 	}