我的routing.dev.yml中的Symfony2循环引用

Question

我正在尝试在我的项目中构建登录和注册表单和进程，但由于某种原因我得到循环引用错误。注册工作正常。问题是我在构建登录表单时。我正在使用这里的教程：

http://symfony.com/doc/current/cookbook/security/form_login_setup.html

当我添加它时，项目仍然有效：

firewalls:
        default:
            anonymous: ~
            http_basic: ~
            form_login:
                login_path: /login_user
                check_path: /login_check

但是当我在控制器中制作路线时，我得到错误：

<?php
// src/AppBundle/Controller/SecurityController.php

// ...
use Symfony\Component\HttpFoundation\Request;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;

    class SecurityController extends Controller
    {
        /**
         * @Route("/login_user", name="login_route")
         */
        public function loginAction(Request $request)
        {
             $authenticationUtils = $this->get('security.authentication_utils');

        // get the login error if there is one
        $error = $authenticationUtils->getLastAuthenticationError();

        // last username entered by the user
        $lastUsername = $authenticationUtils->getLastUsername();

        return $this->render(
            'Frontend/navbar.html.twig',
            array(
                // last username entered by the user
                'last_username' => $lastUsername,
                'error'         => $error,
            )
        );
        }

        /**
         * @Route("/login_check", name="login_check")
         */
        public function loginCheckAction()
        {
            // this controller will not be executed,
            // as the route is handled by the Security system
        }
    }

这是我的routing.dev.yml：

_wdt:
    resource: "@WebProfilerBundle/Resources/config/routing/wdt.xml"
    prefix:   /_wdt

_profiler:
    resource: "@WebProfilerBundle/Resources/config/routing/profiler.xml"
    prefix:   /_profiler

_configurator:
    resource: "@SensioDistributionBundle/Resources/config/routing/webconfigurator.xml"
    prefix:   /_configurator

_errors:
    resource: "@TwigBundle/Resources/config/routing/errors.xml"
    prefix:   /_error

_main:
    resource: routing.yml

这里有什么问题？