diff -r 4950ae4d034f -r 566daffc607d mercurial/hbisect.py
--- a/mercurial/hbisect.py	Wed Jul 19 13:17:49 2017 -0700
+++ b/mercurial/hbisect.py	Wed Apr 03 11:21:27 2019 -0700
@@ -34,7 +34,7 @@
 
     changelog = repo.changelog
     clparents = changelog.parentrevs
-    skip = set([changelog.rev(n) for n in state['skip']])
+    skip = {changelog.rev(n) for n in state['skip']}
 
     def buildancestors(bad, good):
         badrev = min([changelog.rev(n) for n in bad])