diff --git a/src/Symfony/Component/Messenger/Envelope.php b/src/Symfony/Component/Messenger/Envelope.php
index 03fb4c8ea9e12..7741bb4d9bedc 100644
--- a/src/Symfony/Component/Messenger/Envelope.php
+++ b/src/Symfony/Component/Messenger/Envelope.php
@@ -112,7 +112,7 @@ public function last(string $stampFqcn): ?StampInterface
      *
      * @return StampInterface[]|StampInterface[][] The stamps for the specified FQCN, or all stamps by their class name
      *
-     * @psalm-return ($stampFqcn is string : array<class-string<StampInterface>, list<StampInterface>> ? list<TStamp>)
+     * @psalm-return ($stampFqcn is null ? array<class-string<StampInterface>, list<StampInterface>> : list<TStamp>)
      */
     public function all(?string $stampFqcn = null): array
     {