diff --git a/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php b/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
index b3d6e0f46..c1547e52e 100644
--- a/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
+++ b/lib/Doctrine/ORM/Cache/DefaultCacheFactory.php
@@ -181,8 +181,13 @@ class DefaultCacheFactory implements CacheFactory
      */
     public function buildCollectionHydrator(EntityManagerInterface $em, array $mapping)
     {
+        /* @var $targetPersister \Doctrine\ORM\Cache\Persister\CachedPersister */
         $targetPersister = $em->getUnitOfWork()->getEntityPersister($mapping['targetEntity']);
-        return new DefaultCollectionHydrator($em, $targetPersister->getCacheRegion());
+
+        return new DefaultCollectionHydrator(
+            $em,
+            $targetPersister->getCacheRegion()
+        );
     }
 
     /**