diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -1664,7 +1664,7 @@
             cparents = repo.changelog.parents(top)
             patchparent = self.qparents(repo, top)
 
-            inclsubs = checksubstate(repo, hex(patchparent))
+            inclsubs = checksubstate(repo, patchparent)
             if inclsubs:
                 substatestate = repo.dirstate['.hgsubstate']