diff -r 7ae6e3529e37 -r 658b1d28813c mercurial/merge.py
--- a/mercurial/merge.py	Thu Mar 22 22:39:43 2018 +0900
+++ b/mercurial/merge.py	Thu Mar 22 22:56:29 2018 -0400
@@ -706,7 +706,8 @@
             # Does the directory contain any files that are not in the dirstate?
             for p, dirs, files in repo.wvfs.walk(f):
                 for fn in files:
-                    relf = repo.dirstate.normalize(repo.wvfs.reljoin(p, fn))
+                    relf = util.pconvert(repo.wvfs.reljoin(p, fn))
+                    relf = repo.dirstate.normalize(relf)
                     if relf not in repo.dirstate:
                         return f
         return None