Index: django/db/models/options.py
===================================================================
--- django/db/models/options.py	(wersja 16924)
+++ django/db/models/options.py	(kopia robocza)
@@ -436,6 +436,8 @@
         """
         if not self.parents:
             return
+        if model._meta is self:
+            return
         if model in self.parents:
             return [model]
         for parent in self.parents: