diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 9f503bd..454451e 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -436,7 +436,7 @@
             return -1;
         Py_UNICODE_COPY(w->str, v->str,
                         length < v->length ? length : v->length);
-        Py_SETREF(*unicode, w);
+        Py_XSETREF(*unicode, w);
         return 0;
     }