diff --git a/mercurial/upgrade.py b/mercurial/upgrade.py
--- a/mercurial/upgrade.py
+++ b/mercurial/upgrade.py
@@ -142,7 +142,7 @@ class improvement(object):
         return self.name == other.name
 
     def __ne__(self, other):
-        return not self == other
+        return not (self == other)
 
     def __hash__(self):
         return hash(self.name)