diff --git a/core/lib/Drupal/Core/Controller/ControllerResolver.php b/core/lib/Drupal/Core/Controller/ControllerResolver.php
index 7d39389..9ae9788 100644
--- a/core/lib/Drupal/Core/Controller/ControllerResolver.php
+++ b/core/lib/Drupal/Core/Controller/ControllerResolver.php
@@ -104,10 +104,16 @@ protected function createController($controller) {
    */
   protected function doGetArguments(Request $request, $controller, array $parameters) {
     $arguments = parent::doGetArguments($request, $controller, $parameters);
+
+    // The parameter converter overrides the raw request attributes with the
+    // upcasted objects. However, it keeps a backup copy of the original, raw
+    // values in a special request attribute ('_raw'). If a controller argument
+    // has a type hint, we pass it the upcasted object, otherwise we pass it
+    // the original, raw value.
     if ($request->attributes->has('_raw') && $raw = $request->attributes->get('_raw')->all()) {
       foreach ($parameters as $parameter) {
         // Use the raw value if a parameter has no typehint.
-        if (!$parameter->getClass()) {
+        if (!$parameter->getClass() && isset($raw[$parameter->name])) {
           $position = $parameter->getPosition();
           $arguments[$position] = $raw[$parameter->name];
         }
diff --git a/core/modules/image/lib/Drupal/image/Form/ImageEffectDeleteForm.php b/core/modules/image/lib/Drupal/image/Form/ImageEffectDeleteForm.php
index 50bf2bb..15197e4 100644
--- a/core/modules/image/lib/Drupal/image/Form/ImageEffectDeleteForm.php
+++ b/core/modules/image/lib/Drupal/image/Form/ImageEffectDeleteForm.php
@@ -61,7 +61,7 @@ public function getFormID() {
   /**
    * {@inheritdoc}
    */
-  public function buildForm(array $form, array &$form_state, $image_style = NULL, $image_effect = NULL, Request $request = NULL) {
+  public function buildForm(array $form, array &$form_state, ImageStyle $image_style = NULL, $image_effect = NULL, Request $request = NULL) {
     $this->imageStyle = $image_style;
     $this->imageEffect = image_effect_load($image_effect, $this->imageStyle->id());
 
diff --git a/core/modules/system/tests/modules/paramconverter_test/lib/Drupal/paramconverter_test/TestControllers.php b/core/modules/system/tests/modules/paramconverter_test/lib/Drupal/paramconverter_test/TestControllers.php
index d3060e6..cd9b578 100644
--- a/core/modules/system/tests/modules/paramconverter_test/lib/Drupal/paramconverter_test/TestControllers.php
+++ b/core/modules/system/tests/modules/paramconverter_test/lib/Drupal/paramconverter_test/TestControllers.php
@@ -8,21 +8,21 @@
 namespace Drupal\paramconverter_test;
 
 use Drupal\Core\Entity\EntityInterface;
-use Drupal\user\UserInterface;
+use Drupal\node\NodeInterface;
+use Symfony\Component\HttpFoundation\Request;
 
 /**
  * Controller routine for testing the paramconverter.
  */
 class TestControllers {
 
-  public function testUserNodeFoo(UserInterface $user, $node, $foo) {
-    $retval = "user: " . (is_object($user) ? $user->label() : $user);
-    $retval .= ", node: " . (is_object($node) ? $node->label() : $node);
-    $retval .= ", foo: " . (is_object($foo) ? $foo->label() : $foo);
-    return $retval;
+  public function testUserNodeFoo(EntityInterface $user, NodeInterface $node, Request $request) {
+    $foo = $request->attributes->get('foo');
+    $foo = is_object($foo) ? $foo->label() : $foo;
+    return "user: {$user->label()}, node: {$node->label()}, foo: $foo";
   }
 
-  public function testNodeSetParent(EntityInterface $node, EntityInterface $parent) {
-    return "Setting '{$parent->title}' as parent of '{$node->title}'.";
+  public function testNodeSetParent(NodeInterface $node, NodeInterface $parent) {
+    return "Setting '{$parent->label()}' as parent of '{$node->label()}'.";
   }
 }