Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

vendor/symfony/http-kernel/DependencyInjection/ContainerAwareHttpKernel.php

@@ -71,6 +71,11 @@ class ContainerAwareHttpKernel extends HttpKernel
             $this->container->set('request', null, 'request');
             $this->container->leaveScope('request');
 
+            throw $e;
+        } catch (\Throwable $e) {
+            $this->container->set('request', null, 'request');
+            $this->container->leaveScope('request');
+
             throw $e;
         }
 

vendor/symfony/http-kernel/DependencyInjection/FragmentRendererPass.php

@@ -54,7 +54,12 @@ class FragmentRendererPass implements CompilerPassInterface
 
             $class = $container->getParameterBag()->resolveValue($def->getClass());
             $interface = 'Symfony\Component\HttpKernel\Fragment\FragmentRendererInterface';
+
             if (!is_subclass_of($class, $interface)) {
+                if (!class_exists($class, false)) {
+                    throw new \InvalidArgumentException(sprintf('Class "%s" used for service "%s" cannot be found.', $class, $id));
+                }
+
                 throw new \InvalidArgumentException(sprintf('Service "%s" must implement interface "%s".', $id, $interface));
             }
 

vendor/symfony/http-kernel/DependencyInjection/LazyLoadingFragmentHandler.php

@@ -54,6 +54,7 @@ class LazyLoadingFragmentHandler extends FragmentHandler
     /**
      * Adds a service as a fragment renderer.
      *
+     * @param string $name     The service name
      * @param string $renderer The render service id
      */
     public function addRendererService($name, $renderer)