Support tuples of heterogeneous types for empty expanding IN

Pass a list of all the types for the left side of an
IN expression to the visit_empty_set_expr() method, so that
the "empty expanding IN" can produce clauses for each element.

Fixes: #4271
Change-Id: I2738b9df2292ac01afda37f16d4fa56ae7bf9147

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index dd16b6862..de3b7992a 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -865,6 +865,7 @@ class BindParameter(ColumnElement):
     __visit_name__ = 'bindparam'
 
     _is_crud = False
+    _expanding_in_types = ()
 
     def __init__(self, key, value=NO_ARG, type_=None,
                  unique=False, required=NO_ARG,
@@ -1134,6 +1135,15 @@ class BindParameter(ColumnElement):
         else:
             self.type = type_
 
+    def _with_expanding_in_types(self, types):
+        """Return a copy of this :class:`.BindParameter` in
+        the context of an expanding IN against a tuple.
+
+        """
+        cloned = self._clone()
+        cloned._expanding_in_types = types
+        return cloned
+
     def _with_value(self, value):
         """Return a copy of this :class:`.BindParameter` with the given value
         set.