--- a/hgext3rd/topic/revset.py	Sun Aug 14 19:57:58 2016 +0200
+++ b/hgext3rd/topic/revset.py	Tue Aug 16 15:32:54 2016 +0200
@@ -53,7 +53,7 @@
     branch = revset.getstring(args[0], 'ngtip() argument must be a string')
     if branch == '.':
         branch = repo['.'].branch()
-    return subset & destination.ngtip(repo, branch)
+    return subset & revset.baseset(destination.ngtip(repo, branch))
 
 def stackset(repo, subset, x):
     """`stack()`