--- a/mercurial/discovery.py	Fri Mar 13 14:20:13 2015 -0400
+++ b/mercurial/discovery.py	Fri Mar 13 17:00:06 2015 -0400
@@ -218,7 +218,10 @@
     r = repo.set('heads(%ln + %ln)', oldheads, outgoing.missing)
     newheads = list(c.node() for c in r)
     # set some unsynced head to issue the "unsynced changes" warning
-    unsynced = inc and set([None]) or set()
+    if inc:
+        unsynced = set([None])
+    else:
+        unsynced = set()
     return {None: (oldheads, newheads, unsynced)}
 
 def checkheads(repo, remote, outgoing, remoteheads, newbranch=False, inc=False,