immutable.c:7:6: Arrow access from possibly null pointer res: res->x
immutable.c:5:19: Storage res may become null
immutable.c:8:10: Fresh storage returned as unqualified (should be only): res
immutable.c:7:6: Arrow access from possibly null pointer res: res->x
immutable.c:5:19: Storage res may become null
immutable.c:8:10: Fresh storage returned as unqualified (should be only): res