diff -r bea46aed1e1b -r 2cb05e6043be mercurial/revset.py
--- a/mercurial/revset.py	Thu Dec 07 13:20:47 2017 -0800
+++ b/mercurial/revset.py	Sun Oct 22 18:57:42 2017 +0900
@@ -928,8 +928,7 @@
         files = c.manifest().walk(matcher)
 
         fctxs = [c[f].introfilectx() for f in files]
-        a = dagop.filectxancestors(fctxs, followfirst)
-        s = set(c.rev() for c in a)
+        s = dagop.filerevancestors(fctxs, followfirst)
     else:
         s = dagop.revancestors(repo, baseset([c.rev()]), followfirst)