--- a/mercurial/context.py	Sat Jun 30 12:42:49 2018 +0530
+++ b/mercurial/context.py	Thu Jul 12 08:14:21 2018 -0700
@@ -591,7 +591,7 @@
 
     def descendant(self, other):
         """True if other is descendant of this changeset"""
-        return self._repo.changelog.isdescendantrev(other._rev, self._rev)
+        return self._repo.changelog.isancestorrev(self._rev, other._rev)
 
     def walk(self, match):
         '''Generates matching file names.'''