diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php
index efeafad5f0..f86d123d74 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php
@@ -62,6 +62,7 @@ class UnusedTagsPass implements CompilerPassInterface
         'twig.loader',
         'validator.constraint_validator',
         'validator.initializer',
+        'validator.auto_mapper',
     ];
 
     public function process(ContainerBuilder $container)