diff --git a/src/Symfony/Component/Security/Core/User/User.php b/src/Symfony/Component/Security/Core/User/User.php
index ef0ae2f303..68a01fcfc5 100644
--- a/src/Symfony/Component/Security/Core/User/User.php
+++ b/src/Symfony/Component/Security/Core/User/User.php
@@ -67,8 +67,9 @@ final class User implements UserInterface, EquatableInterface
     /**
      * {@inheritdoc}
      */
-    public function getSalt()
+    public function getSalt(): ?string
     {
+        return null;
     }
 
     /**