diff --git a/contributing/code/conventions.rst b/contributing/code/conventions.rst
index 7099ace5db5..05dff1ebf61 100644
--- a/contributing/code/conventions.rst
+++ b/contributing/code/conventions.rst
@@ -129,7 +129,7 @@ the Web Debug Toolbar or by the PHPUnit bridge).
 .. _`@-silencing operator`: https://php.net/manual/en/language.operators.errorcontrol.php
 
 When deprecating a whole class the ``trigger_error()`` call should be placed
-between the namespace and the use declarations, like in this example from
+after the use declarations, like in this example from
 `ServiceRouterLoader`_::
 
     namespace Symfony\Component\Routing\Loader\DependencyInjection;
diff --git a/service_container/definitions.rst b/service_container/definitions.rst
index 5e74bef8ec9..f4d82d776d2 100644
--- a/service_container/definitions.rst
+++ b/service_container/definitions.rst
@@ -89,6 +89,10 @@ fetched from the container::
 
     // gets a specific argument
     $firstArgument = $definition->getArgument(0);
+    
+    // adds a new argument with the name of the argument
+    // $argumentName = the name of the argument in the constructor
+    $argument = $definition->setArgument('$argumentName', $argumentValue);
 
     // adds a new argument
     $definition->addArgument($argument);
@@ -96,7 +100,7 @@ fetched from the container::
     // replaces argument on a specific index (0 = first argument)
     $definition->replaceArgument($index, $argument);
 
-    // replace all previously configured arguments with the passed array
+    // replaces all previously configured arguments with the passed array
     $definition->setArguments($arguments);
 
 .. caution::