self->compare_self()

diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index 4ab1f187133a6842620c4f463b83bf1f3cfd0857..ab46b62c0573269cba6a024b89ab7b9d6f0a7ee6 100644 (file)
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -473,7 +473,7 @@ class CompareMixin(object):
             if obj is None:
                 if operator != '=':
                     raise "Only '=' operator can be used with NULL"
-                return BooleanExpression(self, null(), 'IS')
+                return BooleanExpression(self._compare_self(), null(), 'IS')
             else:
                 obj = self._bind_param(obj)