diff --git a/core/lib/Drupal/Core/Routing/UrlGenerator.php b/core/lib/Drupal/Core/Routing/UrlGenerator.php
index b13d3dbbc915ccc75cf560d1b9f5469c23c6fac2..36ed0f6b6cb55c86b92e2b11e481d2f150a0e1b5 100644
--- a/core/lib/Drupal/Core/Routing/UrlGenerator.php
+++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
@@ -19,6 +19,13 @@
  */
 class UrlGenerator implements UrlGeneratorInterface {
 
+  /**
+   * The route provider.
+   *
+   * @var \Drupal\Core\Routing\RouteProviderInterface
+   */
+  protected $provider;
+
   /**
    * @var RequestContext
    */