1 files changed, 2 insertions, 2 deletions
diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py
index 729ff17e2e..4ff6aed253 100644
--- a/synapse/storage/databases/main/relations.py
+++ b/synapse/storage/databases/main/relations.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import logging
-from typing import List, Optional, Tuple, Union
+from typing import List, Optional, Tuple, Union, cast
 
 import attr
 
@@ -399,7 +399,7 @@ class RelationsWorkerStore(SQLBaseStore):
                     AND relation_type = ?
             """
             txn.execute(sql, (event_id, room_id, RelationTypes.THREAD))
-            count = txn.fetchone()[0]  # type: ignore[index]
+            count = cast(Tuple[int], txn.fetchone())[0]
 
             return count, latest_event_id