The best way I've been able to achieve this is once you begin to iterate through the associative array you can type hint the variable at that point. This will only work if the array holds all of the same class types.
<?php
foreach($myAssociativeArray as $item){
/* @var $item ObjectClass */
Some code here...
}
This should properly pass the ObjectClass type hinting to $item. Again, if you're array holds multiple class types then this solution will not work.