diff --git a/eden/scm/edenscm/ext/extlib/phabricator/diffprops.py b/eden/scm/edenscm/ext/extlib/phabricator/diffprops.py
index 9bdf4d9ab0..b735efdfe4 100644
--- a/eden/scm/edenscm/ext/extlib/phabricator/diffprops.py
+++ b/eden/scm/edenscm/ext/extlib/phabricator/diffprops.py
@@ -6,9 +6,10 @@
 from __future__ import absolute_import
 
 import re
+from typing import Pattern
 
 
-diffrevisionregex = re.compile(r"^Differential Revision:.*/D(\d+)", re.M)
+diffrevisionregex: Pattern[str] = re.compile(r"^Differential Revision:.*/D(\d+)", re.M)
 
 
 def parserevfromcommitmsg(description):