From 72a0685aa40c0a8bde6ccfdde040c5273f1dad16 Mon Sep 17 00:00:00 2001
From: Ryan Weaver <ryan@thatsquality.com>
Date: Sun, 29 Oct 2017 14:17:31 -0400
Subject: [PATCH] Adding warning about non-service arguments

---
 controller.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/controller.rst b/controller.rst
index 832a843b752..1ed5a479ac6 100644
--- a/controller.rst
+++ b/controller.rst
@@ -338,6 +338,13 @@ controller's service config:
 You can of course also use normal :ref:`constructor injection <services-constructor-injection>`
 in your controllers.
 
+.. caution::
+
+    You can *only* pass *services* to your controller arguments in this way. It's
+    not possible, for example, to pass a service parameter as a controller argument.
+    If you need a parameter, use the ``$this->getParameter('kernel.debug')`` shortcut
+    or pass the value through your controller's ``__construct()`` method.
+
 For more information about services, see the :doc:`/service_container` article.
 
 .. _controller-service-arguments-tag: