diff --git a/src/Symfony/Component/DependencyInjection/Definition.php b/src/Symfony/Component/DependencyInjection/Definition.php
index 6f2a3c7e82..8286e9d1e7 100644
--- a/src/Symfony/Component/DependencyInjection/Definition.php
+++ b/src/Symfony/Component/DependencyInjection/Definition.php
@@ -144,7 +144,7 @@ class Definition
      */
     public function setDecoratedService($id, $renamedId = null)
     {
-        if ($renamedId && $id == $renamedId) {
+        if ($renamedId && $id === $renamedId) {
             throw new \InvalidArgumentException(sprintf('The decorated service inner name for "%s" must be different than the service name itself.', $id));
         }