diff --git a/lib/SimpleSAML/Module/ControllerResolver.php b/lib/SimpleSAML/Module/ControllerResolver.php
index 25bfa08fd194178913b6962482970dbfda1753e3..85d39744362857f9a8ce3faff8d8b368736453b6 100644
--- a/lib/SimpleSAML/Module/ControllerResolver.php
+++ b/lib/SimpleSAML/Module/ControllerResolver.php
@@ -44,9 +44,9 @@ class ControllerResolver extends SymfonyControllerResolver implements ArgumentRe
     protected $module;
 
     /** @var array */
-    protected $params;
+    protected $params = [];
 
-    /** @var RouteCollection */
+    /** @var RouteCollection|null */
     protected $routes;
 
 
@@ -172,6 +172,7 @@ class ControllerResolver extends SymfonyControllerResolver implements ArgumentRe
      * Set the configuration to use by the controllers.
      *
      * @param \SimpleSAML\Configuration $config
+     * @return void
      */
     public function setConfiguration(Configuration $config)
     {
@@ -184,6 +185,7 @@ class ControllerResolver extends SymfonyControllerResolver implements ArgumentRe
      * Set the session to use by the controllers.
      *
      * @param \SimpleSAML\Session $session
+     * @return void
      */
     public function setSession(Session $session)
     {