Defer deleted item decref until after the deque is restored to a consistent state.
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index bcdffcb..1924374 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -623,9 +623,9 @@
         if (cmp > 0) {
             PyObject *tgt = deque_popleft(deque, NULL);
             assert (tgt != NULL);
-            Py_DECREF(tgt);
-            if (_deque_rotate(deque, i) == -1)
+            if (_deque_rotate(deque, i))
                 return NULL;
+            Py_DECREF(tgt);
             Py_RETURN_NONE;
         }
         else if (cmp < 0) {
@@ -706,16 +706,16 @@
 deque_del_item(dequeobject *deque, Py_ssize_t i)
 {
     PyObject *item;
+    int rv;
 
-    assert (i >= 0 && i < deque->len);
-    if (_deque_rotate(deque, -i) == -1)
+    assert (i >= 0 && i < Py_SIZE(deque));
+    if (_deque_rotate(deque, -i))
         return -1;
-
     item = deque_popleft(deque, NULL);
+    rv = _deque_rotate(deque, i);
     assert (item != NULL);
     Py_DECREF(item);
-
-    return _deque_rotate(deque, i);
+    return rv;
 }
 
 static int