Issue #3245953 by kristiaanvandeneynde: TwigExtension::drupalTitle() should check for NullRouteMatch

src/TwigExtension.php

@@ -888,10 +888,10 @@ class TwigExtension extends AbstractExtension {
    *   A render array to represent page title.
    */
   public function drupalTitle() {
-    $title = \Drupal::service('title_resolver')->getTitle(
-      \Drupal::request(),
-      \Drupal::routeMatch()->getRouteObject()
-    );
+    $title = NULL;
+    if ($route = \Drupal::routeMatch()->getRouteObject()) {
+      $title = \Drupal::service('title_resolver')->getTitle(\Drupal::request(), $route);
+    }
     $build['#markup'] = render($title);
     $build['#cache']['contexts'] = ['url'];
     return $build;