diff --git a/src/Bundle/ChillMainBundle/Doctrine/ORM/Hydration/FlatHierarchyEntityHydrator.php b/src/Bundle/ChillMainBundle/Doctrine/ORM/Hydration/FlatHierarchyEntityHydrator.php
index 48b6ff875..c389b543d 100644
--- a/src/Bundle/ChillMainBundle/Doctrine/ORM/Hydration/FlatHierarchyEntityHydrator.php
+++ b/src/Bundle/ChillMainBundle/Doctrine/ORM/Hydration/FlatHierarchyEntityHydrator.php
@@ -16,7 +16,7 @@ final class FlatHierarchyEntityHydrator extends ObjectHydrator
         return array_values(iterator_to_array($this->flatListGenerator($this->buildChildrenHashmap(parent::hydrateAllData()))));
     }
 
-    private function flatListGenerator(array $hashMap, ?int $parent = null): Generator
+    private function flatListGenerator(array $hashMap, ?object $parent = null): Generator
     {
         $parent = null === $parent ? null : spl_object_id($parent);
         $hashMap += [$parent => []];