- Added new checks for the common error case of passing mapped classes

or mapped instances into contexts where they are interpreted as
SQL bound parameters; a new exception is raised for this.
fixes #3321

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py
index 09f639163..125fec33f 100644
--- a/lib/sqlalchemy/sql/default_comparator.py
+++ b/lib/sqlalchemy/sql/default_comparator.py
@@ -15,7 +15,7 @@ from .elements import BindParameter, True_, False_, BinaryExpression, \
     Null, _const_expr, _clause_element_as_expr, \
     ClauseList, ColumnElement, TextClause, UnaryExpression, \
     collate, _is_literal, _literal_as_text, ClauseElement, and_, or_, \
-    Slice
+    Slice, Visitable
 from .selectable import SelectBase, Alias, Selectable, ScalarSelect
 
 
@@ -304,7 +304,7 @@ def _check_literal(expr, operator, other):
 
     if isinstance(other, (SelectBase, Alias)):
         return other.as_scalar()
-    elif not isinstance(other, (ColumnElement, TextClause)):
+    elif not isinstance(other, Visitable):
         return expr._bind_param(operator, other)
     else:
         return other