Fixed #21552 -- Allowed the use of None for the iexact lookup.

Thanks Anubhav Joshi for the documentation.

1 files changed, 1 insertions, 1 deletions

diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 43026d2d82..223e516d56 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -1031,7 +1031,7 @@ class Query(object):
         # Interpret '__exact=None' as the sql 'is NULL'; otherwise, reject all
         # uses of None as a query value.
         if value is None:
-            if lookup_type != 'exact':
+            if lookup_type not in ('exact', 'iexact'):
                 raise ValueError("Cannot use None as a query value")
             lookup_type = 'isnull'
             value = True