diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -3521,7 +3521,7 @@
             if self.mq.applied and self.mq.checkapplied and not force:
                 parents = self.dirstate.parents()
                 patches = [s.node for s in self.mq.applied]
-                if parents[0] in patches or parents[1] in patches:
+                if any(p in patches for p in parents):
                     raise error.Abort(errmsg)
 
         def commit(self, text="", user=None, date=None, match=None,