diff --git a/http_cache.rst b/http_cache.rst
index 09dbf84c8db..b6139047cfd 100644
--- a/http_cache.rst
+++ b/http_cache.rst
@@ -137,7 +137,7 @@ method::
 
     class CacheKernel extends HttpCache
     {
-        protected function getOptions()
+        protected function getOptions(): Array
         {
             return [
                 'default_ttl' => 0,