1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 90189869cc..4e658d9a48 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -1235,7 +1235,7 @@ class AuthHandler(BaseHandler):
         return urllib.parse.urlunparse(url_parts)
 
 
-@attr.s
+@attr.s(slots=True)
 class MacaroonGenerator:
 
     hs = attr.ib()