diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 3971062..669b709 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2100,6 +2100,7 @@
                 PyErr_Format(PyExc_ValueError,
                              "%R in __slots__ conflicts with class variable",
                              tmp);
+                Py_DECREF(newslots);
                 goto bad_slots;
             }
             j++;