diff --git a/core/lib/Drupal/Component/DependencyInjection/Container.php b/core/lib/Drupal/Component/DependencyInjection/Container.php
index 06d1a70..6b0df79 100644
--- a/core/lib/Drupal/Component/DependencyInjection/Container.php
+++ b/core/lib/Drupal/Component/DependencyInjection/Container.php
@@ -410,7 +410,7 @@ public function initialized($id) {
   }
 
   /**
-   * Resolves arguments from \stdClass objects to the real values.
+   * Resolves arguments that represent services or variables to the real values.
    *
    * @param array|\stdClass $arguments
    *   The arguments to resolve.
diff --git a/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php b/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
index 6aed08f..c0ec669 100644
--- a/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
+++ b/core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\Component\DependencyInjection\Dumper;
 
-use Symfony\Component\DependencyInjection\Alias;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Parameter;
diff --git a/core/lib/Drupal/Component/DependencyInjection/PhpArrayContainer.php b/core/lib/Drupal/Component/DependencyInjection/PhpArrayContainer.php
index 7c96d07..53c33d9 100644
--- a/core/lib/Drupal/Component/DependencyInjection/PhpArrayContainer.php
+++ b/core/lib/Drupal/Component/DependencyInjection/PhpArrayContainer.php
@@ -191,8 +191,8 @@ protected function resolveServicesAndParameters($arguments) {
     // cases:
     // - A service is denoted by '@service' and not by a \stdClass object.
     // - A parameter is denoted by '%parameter%' and not by a \stdClass object.
-    // - Arguments are traversed recursively, there is no information how deep
-    //   to traverse.
+    // - The depth of the tree representing the arguments is not known in
+    //   advance, so it needs to be fully traversed recursively.
     foreach ($arguments as $key => $argument) {
       if ($argument instanceof \stdClass) {
         $type = $argument->type;
diff --git a/core/lib/Drupal/Core/DependencyInjection/Container.php b/core/lib/Drupal/Core/DependencyInjection/Container.php
index a1b8d56..b4cac53 100644
--- a/core/lib/Drupal/Core/DependencyInjection/Container.php
+++ b/core/lib/Drupal/Core/DependencyInjection/Container.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\DependencyInjection;
 
 use Drupal\Component\DependencyInjection\Container as DrupalContainer;
+use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Extends the Drupal container to set the service ID on the created object.
@@ -17,7 +18,7 @@ class Container extends DrupalContainer {
   /**
    * {@inheritdoc}
    */
-  public function set($id, $service, $scope = DrupalContainer::SCOPE_CONTAINER) {
+  public function set($id, $service, $scope = ContainerInterface::SCOPE_CONTAINER) {
      parent::set($id, $service, $scope);
 
     // Ensure that the _serviceId property is set on synthetic services as well.
diff --git a/core/modules/update/src/Tests/UpdateTestBase.php b/core/modules/update/src/Tests/UpdateTestBase.php
index faec496..33ee105 100644
--- a/core/modules/update/src/Tests/UpdateTestBase.php
+++ b/core/modules/update/src/Tests/UpdateTestBase.php
@@ -35,7 +35,7 @@ protected function setUp() {
 
     // Change the root path which Update Manager uses to install and update
     // projects to be inside the testing site directory. See
-    // \Drupal\update\UpdateRootFactory::get() for equivalent changes to the
+    // \Drupal\updateUpdateRootFactory::get() for equivalent changes to the
     // test child site.
     $request = \Drupal::request();
     $update_root = $this->container->get('update.root') . '/' . DrupalKernel::findSitePath($request);