diff --cc core/modules/shortcut/shortcut.module
index 601a149,51a6f4b..0000000
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@@ -297,8 -297,11 +297,8 @@@ function shortcut_preprocess_page(&$var
    // we do not want to display it on "access denied" or "page not found"
    // pages).
    if (shortcut_set_edit_access()->isAllowed() && !\Drupal::request()->attributes->has('exception')) {
-     $link = current_path();
+     $link = \Drupal::routeMatch()->getUrl()->toString();
 -    if (!($url = \Drupal::pathValidator()->getUrlIfValid($link))) {
 -      // Bail out early if we couldn't find a matching route.
 -      return;
 -    }
 +    $route_match = \Drupal::routeMatch();
  
      $query = array(
        'link' => $link,
diff --git a/core/lib/Drupal/Core/Render/Element/RenderElement.php b/core/lib/Drupal/Core/Render/Element/RenderElement.php
index a621234..bd30b47 100644
--- a/core/lib/Drupal/Core/Render/Element/RenderElement.php
+++ b/core/lib/Drupal/Core/Render/Element/RenderElement.php
@@ -249,10 +249,12 @@ public static function preRenderAjaxForm($element) {
       }
 
       // Change path to URL.
-      $settings['url'] = NULL;
       if (isset($settings['url']) && $settings['url'] instanceof Url) {
         $settings['url'] = $settings['url']->setOptions($settings['options'])->toString();
       }
+      else {
+        $settings['url'] = NULL;
+      }
       unset($settings['options']);
 
       // Add special data to $settings['submit'] so that when this element
diff --git a/core/modules/file/src/Element/ManagedFile.php b/core/modules/file/src/Element/ManagedFile.php
index 75bd1a4..34c20e8 100644
--- a/core/modules/file/src/Element/ManagedFile.php
+++ b/core/modules/file/src/Element/ManagedFile.php
@@ -145,7 +145,7 @@ public static function processManagedFile(&$element, FormStateInterface $form_st
     $element['#tree'] = TRUE;
 
     $ajax_settings = [
-      'path' => 'file/ajax',
+      'url' => Url::fromRoute('file.ajax_upload'),
       'options' => [
         'query' => [
           'element_parents' => implode('/', $element['#array_parents']),
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index cb9aa7f..5b8c4ba 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -240,7 +240,12 @@ function system_hook_info() {
  * Implements hook_theme_suggestions_HOOK().
  */
 function system_theme_suggestions_html(array $variables) {
-  $path_args = explode('/', Url::fromRoute('<current>')->getInternalPath());
+  if (\Drupal::service('path.matcher')->isFrontPage()) {
+    $path_args = [''];
+  }
+  else {
+    $path_args = explode('/', Url::fromRoute('<current>')->getInternalPath());
+  }
   return theme_get_suggestions($path_args, 'html');
 }
 
@@ -248,7 +253,12 @@ function system_theme_suggestions_html(array $variables) {
  * Implements hook_theme_suggestions_HOOK().
  */
 function system_theme_suggestions_page(array $variables) {
-  $path_args = explode('/', Url::fromRoute('<current>')->getInternalPath());
+  if (\Drupal::service('path.matcher')->isFrontPage()) {
+    $path_args = [''];
+  }
+  else {
+    $path_args = explode('/', Url::fromRoute('<current>')->getInternalPath());
+  }
   return theme_get_suggestions($path_args, 'page');
 }
 
diff --git a/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php b/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php
index 6883d16..9f4558b 100644
--- a/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php
+++ b/core/modules/views_ui/src/Form/Ajax/ConfigHandler.php
@@ -8,7 +8,6 @@
 namespace Drupal\views_ui\Form\Ajax;
 
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\Routing\RouteMatch;
 use Drupal\Core\Url;
 use Drupal\views\ViewStorageInterface;
 use Drupal\views\ViewExecutable;