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

vendor/symfony/dependency-injection/Compiler/CheckCircularReferencesPass.php

@@ -0,0 +1,77 @@
+<?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\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+/**
+ * Checks your services for circular references.
+ *
+ * References from method calls are ignored since we might be able to resolve
+ * these references depending on the order in which services are called.
+ *
+ * Circular reference from method calls will only be detected at run-time.
+ *
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+class CheckCircularReferencesPass implements CompilerPassInterface
+{
+    private $currentPath;
+    private $checkedNodes;
+
+    /**
+     * Checks the ContainerBuilder object for circular references.
+     *
+     * @param ContainerBuilder $container The ContainerBuilder instances
+     */
+    public function process(ContainerBuilder $container)
+    {
+        $graph = $container->getCompiler()->getServiceReferenceGraph();
+
+        $this->checkedNodes = array();
+        foreach ($graph->getNodes() as $id => $node) {
+            $this->currentPath = array($id);
+
+            $this->checkOutEdges($node->getOutEdges());
+        }
+    }
+
+    /**
+     * Checks for circular references.
+     *
+     * @param ServiceReferenceGraphEdge[] $edges An array of Edges
+     *
+     * @throws ServiceCircularReferenceException When a circular reference is found.
+     */
+    private function checkOutEdges(array $edges)
+    {
+        foreach ($edges as $edge) {
+            $node = $edge->getDestNode();
+            $id = $node->getId();
+
+            if (empty($this->checkedNodes[$id])) {
+                $searchKey = array_search($id, $this->currentPath);
+                $this->currentPath[] = $id;
+
+                if (false !== $searchKey) {
+                    throw new ServiceCircularReferenceException($id, array_slice($this->currentPath, $searchKey));
+                }
+
+                $this->checkOutEdges($node->getOutEdges());
+
+                $this->checkedNodes[$id] = true;
+                array_pop($this->currentPath);
+            }
+        }
+    }
+}