User reference prevents node from saving due to ambiguous uid column

To reproduce, Drupal 7 alpha and the latest (2010 June 21) CCK 7.x-2.x: Add a userreference field (with the checkbox widget) to a node, then go to add a node of that type and check at least one user.

Drupal 7 prints the nice, bland, unexplanatory error: "The website encountered an unexpected error. Please try again later."

The error log reports:

PDOException: SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'uid' in where clause is ambiguous: SELECT u.uid AS uid, u.name AS name, u.status AS status, r.rid AS rid FROM {users} u INNER JOIN {users_roles} r ON u.uid = r.uid WHERE (u.status IN (:db_condition_placeholder_0, :db_condition_placeholder_1)) AND (r.rid IN (:db_condition_placeholder_2, :db_condition_placeholder_3, :db_condition_placeholder_4)) AND (uid IN (:db_condition_placeholder_5, :db_condition_placeholder_6)) ORDER BY name ASC; Array ( [:db_condition_placeholder_0] => 1 [:db_condition_placeholder_1] => 0 [:db_condition_placeholder_2] => 4 [:db_condition_placeholder_3] => 0 [:db_condition_placeholder_4] => 0 [:db_condition_placeholder_5] => 14 [:db_condition_placeholder_6] => 7 ) in _user_reference_potential_references_standard() (line 485 of /var/local/drupal/dgd7/drupal/sites/default/modules/cck/modules/user_reference/user_reference.module).

Seems PDO should be smart enough to figure this one out but i guess user_reference needs to do a little more handholding.