1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py

index c7e3015b5d..56d6afb863 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -678,7 +678,7 @@ def resolve_events_with_store(
         )
 
 
-@attr.s
+@attr.s(slots=True)
 class StateResolutionStore:
     """Interface that allows state resolution algorithms to access the database
     in well defined way.