Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/validator/Mapping/Loader/XmlFilesLoader.php

@@ -0,0 +1,31 @@
+<?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\Component\Validator\Mapping\Loader;
+
+/**
+ * Loads validation metadata from a list of XML files.
+ *
+ * @author Bulat Shakirzyanov <mallluhuct@gmail.com>
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @see FilesLoader
+ */
+class XmlFilesLoader extends FilesLoader
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getFileLoaderInstance($file)
+    {
+        return new XmlFileLoader($file);
+    }
+}