Added a note about inlined private services

Author: javiereguiluz

book/service_container.rst

@@ -1001,6 +1001,13 @@ By default only public services are shown, but you can also view private service
 
     $ php app/console container:debug --show-private
 
+.. note::
+
+    If a private service is only used as an argument to just one other service,
+    it won't be displayed by the ``container:debug`` command, even when using
+    the ``--show-private`` option. See :ref:`inlined-private-services` for a
+    more detailed explanation.
+
 You can get more detailed information about a particular service by specifying
 its id:
 

components/dependency_injection/advanced.rst

@@ -18,6 +18,8 @@ However, there are use-cases when you don't want a service to be public. This
 is common when a service is only defined because it could be used as an
 argument for another service.
 
+.. _inlined-private-services:
+
 .. note::
 
     If you use a private service as an argument to only one other service,