diff --git a/symfony/framework-bundle/4.2/src/Kernel.php b/symfony/framework-bundle/4.2/src/Kernel.php
index 793761a7..58086ddf 100644
--- a/symfony/framework-bundle/4.2/src/Kernel.php
+++ b/symfony/framework-bundle/4.2/src/Kernel.php
@@ -13,9 +13,9 @@ class Kernel extends BaseKernel
 {
     use MicroKernelTrait;
 
-    const CONFIG_EXTS = '.{php,xml,yaml,yml}';
+    private const CONFIG_EXTS = '.{php,xml,yaml,yml}';
 
-    public function registerBundles()
+    public function registerBundles(): iterable
     {
         $contents = require $this->getProjectDir().'/config/bundles.php';
         foreach ($contents as $class => $envs) {
@@ -25,7 +25,7 @@ class Kernel extends BaseKernel
         }
     }
 
-    protected function configureContainer(ContainerBuilder $container, LoaderInterface $loader)
+    protected function configureContainer(ContainerBuilder $container, LoaderInterface $loader): void
     {
         $container->addResource(new FileResource($this->getProjectDir().'/config/bundles.php'));
         $container->setParameter('container.dumper.inline_class_loader', true);
@@ -37,7 +37,7 @@ class Kernel extends BaseKernel
         $loader->load($confDir.'/{services}_'.$this->environment.self::CONFIG_EXTS, 'glob');
     }
 
-    protected function configureRoutes(RouteCollectionBuilder $routes)
+    protected function configureRoutes(RouteCollectionBuilder $routes): void
     {
         $confDir = $this->getProjectDir().'/config';