DQL permits partial select using SQL

The following code is not correct DQL and should (I think?) throw an error:

$query = $em->createQuery("SELECT g.id, g.name FROM Entity\Group g ORDER BY g.name ASC");

...to force the user to use SELECT partial g.

...

Instead, it causes very funny behaviour. eg. when iterating, objects are passed to the foreach in the following pattern:

$groups = $query->iterate();
foreach(...) {
1st time: $groups = array( [0] => object )
2nd time: $groups = array( [1] => object )
3rd time: $groups = array( [2] => object )
}