diff --git a/reference/configuration/kernel.rst b/reference/configuration/kernel.rst
index c009fb3ec20..4107987e5a3 100644
--- a/reference/configuration/kernel.rst
+++ b/reference/configuration/kernel.rst
@@ -81,9 +81,9 @@ method to return the right project directory::
     {
         // ...
 
-        public function getProjectDir()
+        public function getProjectDir(): string
         {
-            return realpath(__DIR__.'/../');
+            return \dirname(__DIR__);
         }
     }