diff -r ff72bd52d56a -r 9d2b2df2c2ba mercurial/windows.py
--- a/mercurial/windows.py	Fri Mar 06 10:52:44 2020 +0100
+++ b/mercurial/windows.py	Fri Mar 06 13:27:41 2020 -0500
@@ -535,13 +535,11 @@
         cache = dircache.get(dir, None)
         if cache is None:
             try:
-                dmap = dict(
-                    [
-                        (normcase(n), s)
-                        for n, k, s in listdir(dir, True)
-                        if getkind(s.st_mode) in _wantedkinds
-                    ]
-                )
+                dmap = {
+                    normcase(n): s
+                    for n, k, s in listdir(dir, True)
+                    if getkind(s.st_mode) in _wantedkinds
+                }
             except OSError as err:
                 # Python >= 2.5 returns ENOENT and adds winerror field
                 # EINVAL is raised if dir is not a directory.