diff --git a/src/Bundle/ChillEventBundle/Controller/ParticipationController.php b/src/Bundle/ChillEventBundle/Controller/ParticipationController.php
index 1929beac1..a2a82c88f 100644
--- a/src/Bundle/ChillEventBundle/Controller/ParticipationController.php
+++ b/src/Bundle/ChillEventBundle/Controller/ParticipationController.php
@@ -16,6 +16,8 @@ use Chill\EventBundle\Entity\Event;
 use Chill\EventBundle\Entity\Participation;
 use Chill\EventBundle\Form\ParticipationType;
 use Chill\EventBundle\Security\Authorization\ParticipationVoter;
+use Doctrine\Common\Collections\Collection;
+use Doctrine\Common\Collections\ReadableCollection;
 use LogicException;
 use Psr\Log\LoggerInterface;
 use RuntimeException;
@@ -509,7 +511,7 @@ class ParticipationController extends AbstractController
     /**
      * @return \Symfony\Component\Form\FormInterface
      */
-    protected function createEditFormMultiple(ArrayIterator $participations, Event $event)
+    protected function createEditFormMultiple(Collection $participations, Event $event)
     {
         $form = $this->createForm(
             \Symfony\Component\Form\Extension\Core\Type\FormType::class,
@@ -638,6 +640,7 @@ class ParticipationController extends AbstractController
         $ignoredParticipations = $newParticipations = [];
 
         foreach ($participations as $participation) {
+            /** @var Participation $participation */
             // check for authorization
             $this->denyAccessUnlessGranted(
                 ParticipationVoter::CREATE,
diff --git a/src/Bundle/ChillEventBundle/Entity/Event.php b/src/Bundle/ChillEventBundle/Entity/Event.php
index d55a7b8a8..cc762e979 100644
--- a/src/Bundle/ChillEventBundle/Entity/Event.php
+++ b/src/Bundle/ChillEventBundle/Entity/Event.php
@@ -160,11 +160,11 @@ class Event implements HasCenterInterface, HasScopeInterface
     }
 
     /**
-     * @return ArrayIterator|Collection|Traversable
+     * @return Collection<Participation>
      */
     public function getParticipations()
     {
-        return $this->getParticipationsOrdered();
+        return new ArrayCollection(iterator_to_array($this->getParticipationsOrdered()));
     }
 
     /**