Handled the scenario when no entity manager is passed with closure query builder.

src/Symfony/Bridge/Doctrine/Form/ChoiceList/ORMQueryBuilderLoader.php

@@ -49,6 +49,10 @@ class ORMQueryBuilderLoader implements EntityLoaderInterface
         }
 
         if ($queryBuilder instanceof \Closure) {
+            if (!$manager instanceof EntityManager) {
+                throw new UnexpectedTypeException($manager, 'Doctrine\ORM\EntityManager');
+            }
+
             $queryBuilder = $queryBuilder($manager->getRepository($class));
 
             if (!$queryBuilder instanceof QueryBuilder) {

src/Symfony/Bridge/Doctrine/Tests/Form/ChoiceList/ORMQueryBuilderLoaderTest.php

@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Doctrine\Tests\Form\ChoiceList;
+
+use Symfony\Bridge\Doctrine\Form\ChoiceList\ORMQueryBuilderLoader;
+
+class ORMQueryBuilderLoaderTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @expectedException \Symfony\Component\Form\Exception\UnexpectedTypeException
+     */
+    public function testItOnlyWorksWithQueryBuilderOrClosure()
+    {
+        new ORMQueryBuilderLoader(new \stdClass());
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Form\Exception\UnexpectedTypeException
+     */
+    public function testClosureRequiresTheEntityManager()
+    {
+        $closure = function () {};
+
+        new ORMQueryBuilderLoader($closure);
+    }
+}