From e448f979d1ad138f91b8bee5a19f911aed1f2e69 Mon Sep 17 00:00:00 2001
From: Arie Bovenberg <a.c.bovenberg@gmail.com>
Date: Fri, 21 Jan 2022 17:02:50 +0100
Subject: [PATCH] add empty slots to three more base classes

---
 lib/sqlalchemy/sql/operators.py | 2 ++
 lib/sqlalchemy/sql/visitors.py  | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index cf61f26376..255e77b7f9 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -57,6 +57,8 @@ _T = TypeVar("_T", bound=Any)
 class OperatorType(Protocol):
     """describe an op() function."""
 
+    __slots__ = ()
+
     __name__: str
 
     def __call__(
diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py
index 78384782b8..04cd529fbd 100644
--- a/lib/sqlalchemy/sql/visitors.py
+++ b/lib/sqlalchemy/sql/visitors.py
@@ -184,6 +184,8 @@ class _HasTraversalDispatch:
 
     """
 
+    __slots__ = ()
+
     def __init_subclass__(cls) -> None:
         cls._generate_traversal_dispatch()
         super().__init_subclass__()
@@ -299,6 +301,8 @@ class InternalTraversal(_HasTraversalDispatch):
 
     """
 
+    __slots__ = ()
+
     dp_has_cache_key = symbol("HC")
     """Visit a :class:`.HasCacheKey` object."""
 
-- 
2.47.3