diff --git a/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php b/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
index a7a0a3aec3..8f14fe58d9 100644
--- a/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
+++ b/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
@@ -211,7 +211,7 @@ class MessengerPass implements CompilerPassInterface
         }
 
         if ($type->isBuiltin()) {
-            throw new RuntimeException(sprintf('Invalid handler service "%s": type-hint of argument "$%s" in method "%s::__invoke()" must be a class , "%s" given.', $serviceId, $parameters[0]->getName(), $handlerClass->getName(), $type));
+            throw new RuntimeException(sprintf('Invalid handler service "%s": type-hint of argument "$%s" in method "%s::__invoke()" must be a class , "%s" given.', $serviceId, $parameters[0]->getName(), $handlerClass->getName(), $type instanceof \ReflectionNamedType ? $type->getName() : (string) $type));
         }
 
         return [$parameters[0]->getType()->getName()];