diff --git a/core/lib/Drupal/Core/CoreBundle.php b/core/lib/Drupal/Core/CoreBundle.php
index 4ec42b9..158b285 100644
--- a/core/lib/Drupal/Core/CoreBundle.php
+++ b/core/lib/Drupal/Core/CoreBundle.php
@@ -294,7 +294,6 @@ public function build(ContainerBuilder $container) {
     // Add a compiler pass for registering event subscribers.
     $container->addCompilerPass(new RegisterKernelListenersPass(), PassConfig::TYPE_AFTER_REMOVING);
     $container->addCompilerPass(new RegisterAccessChecksPass());
-    // Add a compiler pass for upcasting of entity route parameters.
     $container->addCompilerPass(new RegisterParamConvertersPass());
     $container->addCompilerPass(new RegisterRouteEnhancersPass());
   }
diff --git a/core/lib/Drupal/Core/ParamConverter/EntityConverter.php b/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
index f28906f..716b41e 100644
--- a/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
+++ b/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
@@ -12,8 +12,7 @@
 use Drupal\Core\Entity\EntityManager;
 
 /**
- * This class allows the upcasting of entity ids to the respective entity
- * object.
+ * Allows upcasting of entity ids to the respective entity object.
  */
 class EntityConverter implements ParamConverterInterface {
 
@@ -39,9 +38,9 @@ public function __construct(EntityManager $entityManager) {
    *
    * If there is a type denoted in the route options it will try to upcast to
    * it, if there is no definition in the options it will try to upcast to an
-   * entity type of that name. If the chosen enity type does not exists it will
+   * entity type of that name. If the chosen enity type does not exist it will
    * leave the variable untouched.
-   * If the entity type exist, but there is no entity with the given id it will
+   * If the entity type exists, but there is no entity with the given id it will
    * convert the variable to NULL.
    *
    * Example:
@@ -74,7 +73,7 @@ public function process(array &$variables, Route $route, array &$converted) {
     $entityTypes = array_keys($this->entityManager->getDefinitions());
 
     foreach ($variable_names as $name) {
-      // Do not process this variable if it's already marked as converted.
+      // Do not process this variable if it is already marked as converted.
       if (in_array($name, $converted)) {
         continue;
       }
diff --git a/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php b/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
index be5676e..1249e87 100644
--- a/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
+++ b/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
@@ -16,10 +16,9 @@
 use Drupal\Core\ParamConverter\ParamConverterInterface;
 
 /**
- * Provides a service which allows to enhance (say alter) the arguments coming
- * from the URL.
+ * Provides a service which allows to enhance (say alter) the URL arguments.
  *
- * A typical use case for this would be upcasting a node id to a node entity.
+ * A typical use case for this would be upcasting a node id to a node object.
  *
  * This class will not enhance any of the arguments itself, but allow other
  * services to register to do so.
@@ -64,21 +63,21 @@ public function enhance(array $defaults, Request $request) {
     // This array will collect the names of all variables which have been
     // altered by a converter.
     // This serves two purposes:
-    // 1. It might prevent converters later in the pipeline to process
+    // 1. It might prevent converters later in the pipeline from processing
     //    a variable again.
-    // 2. To check if upcasting was successfull after each converter had
+    // 2. To check if upcasting was successful after each converter had
     //    a go. See below.
-    $converters = array();
+    $converted = array();
 
     $route = $defaults[RouteObjectInterface::ROUTE_OBJECT];
 
     foreach ($this->converters as $converter) {
-      $converter->process($defaults, $route, $converters);
+      $converter->process($defaults, $route, $converted);
     }
 
     // Check if all upcasting yielded a result.
     // If an upcast value is NULL do a 404.
-    foreach ($converters as $variable) {
+    foreach ($converted as $variable) {
       if ($defaults[$variable] === NULL) {
         throw new NotFoundHttpException();
       }
diff --git a/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php b/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
index 14a0422..860eaae 100644
--- a/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/ParamConverter/UpcastingTest.php
@@ -13,7 +13,7 @@
 use Drupal\simpletest\WebTestBase;
 
 /**
- * Web tests for the upcasting.
+ * Web tests for upcasting.
  */
 class UpcastingTest extends WebTestBase {
 
@@ -33,11 +33,11 @@ public static function getInfo() {
   /**
    * Confirms that all parameters are converted as expected.
    *
-   * All of these requests end up being proccessed by a controller with this
-   * the signature: f($user, $node, $foo) returning either values or labels
-   * like "user: Dries, node: First post, foo: bar"
+   * All of these requests end up being proccessed by a controller with the
+   * signature testUserNodeFoo($user, $node, $foo) returning either values or
+   * labels like "user: Dries, node: First post, foo: bar".
    *
-   * The tests shuffle the parameters around an checks if the right thing is
+   * The tests shuffle the parameters around and check if the right things are
    * happening.
    */
   public function testUpcasting() {