diff --git a/src/Bridge/Doctrine/DBAL/Types/AbstractEnumType.php b/src/Bridge/Doctrine/DBAL/Types/AbstractEnumType.php
index 75056606..7d5ebd03 100644
--- a/src/Bridge/Doctrine/DBAL/Types/AbstractEnumType.php
+++ b/src/Bridge/Doctrine/DBAL/Types/AbstractEnumType.php
@@ -91,7 +91,7 @@ public function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $pla
     /**
      * {@inheritdoc}
      */
-    public function getDefaultLength(AbstractPlatform $platform)
+    public function getDefaultLength(AbstractPlatform $platform): ?int
     {
         return $platform->getVarcharDefaultLength();
     }