diff --git a/core/lib/Drupal/Core/Routing/AccessAwareRouter.php b/core/lib/Drupal/Core/Routing/AccessAwareRouter.php
index 916c384ecd77f5fb8a4a2df70600b113e9861e25..b509d31ac802a65e640f8ee1ba3b7f818f976bf3 100644
--- a/core/lib/Drupal/Core/Routing/AccessAwareRouter.php
+++ b/core/lib/Drupal/Core/Routing/AccessAwareRouter.php
@@ -89,7 +89,7 @@ public function getContext() {
    * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
    *   Thrown when access checking failed.
    */
-  public function matchRequest(Request $request) {
+  public function matchRequest(Request $request): array {
     $parameters = $this->router->matchRequest($request);
     $request->attributes->add($parameters);
     $this->checkAccess($request);
diff --git a/core/lib/Drupal/Core/Routing/AccessAwareRouterInterface.php b/core/lib/Drupal/Core/Routing/AccessAwareRouterInterface.php
index 7b0c1c1fd320fd691b0f5549cfaf1c9ac3f0cb2c..3d3047ab120f544d15a155909dacb34a51643c1b 100644
--- a/core/lib/Drupal/Core/Routing/AccessAwareRouterInterface.php
+++ b/core/lib/Drupal/Core/Routing/AccessAwareRouterInterface.php
@@ -22,7 +22,7 @@ interface AccessAwareRouterInterface extends RouterInterface, RequestMatcherInte
    * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
    *   Thrown when access checking failed.
    */
-  public function matchRequest(Request $request);
+  public function matchRequest(Request $request): array;
 
   /**
    * {@inheritdoc}
diff --git a/core/lib/Drupal/Core/Routing/Router.php b/core/lib/Drupal/Core/Routing/Router.php
index bf9e7620deb895e007caa191ecbfedbf74fb5f0a..19d738b75854a120591adde010e983205c1b1ba0 100644
--- a/core/lib/Drupal/Core/Routing/Router.php
+++ b/core/lib/Drupal/Core/Routing/Router.php
@@ -106,7 +106,7 @@ public function match($pathinfo) {
   /**
    * {@inheritdoc}
    */
-  public function matchRequest(Request $request) {
+  public function matchRequest(Request $request): array {
     try {
       $collection = $this->getInitialRouteCollection($request);
     }