Issue #26494: Fixed crash on iterating exhausting iterators.
Affected classes are generic sequence iterators, iterators of bytearray,
list, tuple, set, frozenset, dict, OrderedDict and corresponding views.
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 5d72806..550719f 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -966,8 +966,8 @@
         return item;
     }
 
-    Py_DECREF(seq);
     it->it_seq = NULL;
+    Py_DECREF(seq);
     return NULL;
 }