diff -r 0132221c25cd -r 876494fd967d mercurial/filemerge.py
--- a/mercurial/filemerge.py	Mon Sep 24 14:46:37 2018 -0700
+++ b/mercurial/filemerge.py	Thu Jan 17 09:17:12 2019 -0800
@@ -462,7 +462,6 @@
     Generic driver for _imergelocal and _imergeother
     """
     assert localorother is not None
-    tool, toolpath, binary, symlink, scriptfn = toolconf
     r = simplemerge.simplemerge(repo.ui, fcd, fca, fco, label=labels,
                                 localorother=localorother)
     return True, r