diff --git a/core/lib/Drupal/Core/DependencyInjection/Dumper/PhpArrayDumper.php b/core/lib/Drupal/Core/DependencyInjection/Dumper/PhpArrayDumper.php
index d562595..14c71e6 100644
--- a/core/lib/Drupal/Core/DependencyInjection/Dumper/PhpArrayDumper.php
+++ b/core/lib/Drupal/Core/DependencyInjection/Dumper/PhpArrayDumper.php
@@ -217,11 +217,11 @@ protected function getServiceAliasDefinition($id)
   {
     if ($id->isPublic()) {
       return [
-        'alias' => '@' . $id,
+        'alias' => '@' . (string) $id,
       ];
     } else {
       return [
-        'alias' => '@' . $id,
+        'alias' => '@' . (string) $id,
         'public' => FALSE,
       ];
     }
diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/PhpArray/ContainerTest.php b/core/tests/Drupal/Tests/Core/DependencyInjection/PhpArray/ContainerTest.php
index b7e65d6..7ce8970 100644
--- a/core/tests/Drupal/Tests/Core/DependencyInjection/PhpArray/ContainerTest.php
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/PhpArray/ContainerTest.php
@@ -404,7 +404,7 @@ protected function getMockContainerDefinition() {
       ),
     );
     $services['service.provider_alias'] = array(
-      'alias' => 'service.provider',
+      'alias' => '@service.provider',
     );
 
     $services['service_using_array'] = array(