diff --git a/src/Symfony/Component/DependencyInjection/Compiler/RegisterServiceSubscribersPass.php b/src/Symfony/Component/DependencyInjection/Compiler/RegisterServiceSubscribersPass.php
index 8c81452b315a6..f8dba86a0b547 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/RegisterServiceSubscribersPass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/RegisterServiceSubscribersPass.php
@@ -74,9 +74,6 @@ protected function processValue($value, $isRoot = false)
             if ($optionalBehavior = '?' === $type[0]) {
                 $type = substr($type, 1);
                 $optionalBehavior = ContainerInterface::IGNORE_ON_INVALID_REFERENCE;
-            } elseif ($optionalBehavior = '!' === $type[0]) {
-                $type = substr($type, 1);
-                $optionalBehavior = ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE;
             }
             if (is_int($key)) {
                 $key = $type;