--- a/mercurial/templateutil.py	Sun Mar 15 15:12:44 2020 +0900
+++ b/mercurial/templateutil.py	Sun Mar 15 22:01:38 2020 +0900
@@ -474,7 +474,7 @@
         return bool(self._revs)
 
     def tovalue(self, context, mapping):
-        return list(self._revs)
+        return self._revs
 
 
 class _mappingsequence(wrapped):