diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -3110,10 +3110,14 @@ def graft(ui, repo, *revs, **opts):
     # check for ancestors of dest branch
     crev = repo['.'].rev()
     ancestors = repo.changelog.ancestors([crev], inclusive=True)
+    # Cannot use x.remove(y) on smart set, this has to be a list.
+    # XXX make this lazy in the future
+    revs = list(revs)
     # don't mutate while iterating, create a copy
     for rev in list(revs):
         if rev in ancestors:
             ui.warn(_('skipping ancestor revision %s\n') % rev)
+            # XXX remove on list is slow
             revs.remove(rev)
     if not revs:
         return -1
diff --git a/tests/test-graft.t b/tests/test-graft.t
--- a/tests/test-graft.t
+++ b/tests/test-graft.t
@@ -571,3 +571,14 @@ All copies of a cset
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     2
   
+
+graft works on complex revset
+
+  $ hg graft 'origin(13) or destination(origin(13))'
+  skipping ancestor revision 21
+  skipping ancestor revision 22
+  skipping revision 2 (already grafted to 22)
+  grafting revision 7
+  grafting revision 13
+  grafting revision 19
+  merging b