//AppController.php
class AppController extends Controller {

    var $components = array(
        'Auth', 'Session','Actions'
    );
...

//ActionsComponent.php

App::uses('Component', 'Controller');
ClassRegistry::init('Action');

class ActionsComponent extends Component {

    public function initialize(&$controller, $settings = array()) {
        // saving the controller reference for later use
        $this->controller =& $controller;                     //line 10
    }



Result:

Notice (8): Indirect modification of overloaded property ActionsComponent::$controller has no effect [APP/Controller/Component/ActionsComponent.php, line 10]
Code Context
        }
        foreach ($list as $name) {
            $result = call_user_func_array(array($this->_loaded[$name], $callback), compact('subject') + $params);
$controller = object(CakeErrorController) {}
$settings = array()
ActionsComponent::initialize() - APP/Controller/Component/ActionsComponent.php, line 10
ObjectCollection::trigger() - CORE/Cake/Utility/ObjectCollection.php, line 130
call_user_func - [internal], line ??
CakeEventManager::dispatch() - CORE/Cake/Event/CakeEventManager.php, line 246
Controller::startupProcess() - CORE/Cake/Controller/Controller.php, line 670
CakeErrorController::__construct() - CORE/Cake/Controller/CakeErrorController.php, line 63
ExceptionRenderer::_getController() - CORE/Cake/Error/ExceptionRenderer.php, line 151
ExceptionRenderer::__construct() - CORE/Cake/Error/ExceptionRenderer.php, line 92
ErrorHandler::handleException() - CORE/Cake/Error/ErrorHandler.php, line 126
[main] - [internal], line ??

Fatal error: Cannot assign by reference to overloaded object in /home/dev/public_html/app/Controller/Component/ActionsComponent.php on line 10