mercurial/cmdutil.py

--- a/mercurial/cmdutil.py	Thu Sep 03 11:07:47 2020 -0400
+++ b/mercurial/cmdutil.py	Tue Sep 01 18:08:24 2020 +0530
@@ -46,7 +46,6 @@
     phases,
     pycompat,
     repair,
-    requirements,
     revlog,
     rewriteutil,
     scmutil,
@@ -1359,7 +1358,7 @@
         if cl:
             r = repo.unfiltered().changelog
         elif dir:
-            if requirements.TREEMANIFEST_REQUIREMENT not in repo.requirements:
+            if not scmutil.istreemanifest(repo):
                 raise error.Abort(
                     _(
                         b"--dir can only be used on repos with "