**Error found:** Apparently the problem was that another class 'Edit' which extends 'Slide' was mispelled in the class-declaration. Instead of reporting a missing class 'Edit' it gave me that weird error.

---

I am trying to create an edit page in the Backend for my Entity. I have succeeded in setting up the Grid with help of several tutorials, but when I try to call upon the edit page I get just a blank page and following error in my php error.log: 

    [Wed May 24 12:11:10.565841 2017] [:error] [pid 29789] [client 192.168.144.27:58131] PHP Fatal error:  
    Uncaught TypeError: 
    Argument 1 passed to Myvendor\\Slideshow\\Controller\\Adminhtml\\Slide::__construct() must be an instance of 
	    Magento\\Backend\\App\\Action\\Context, instance of Magento\\Framework\\ObjectManager\\ObjectManager given,
    called in /var/www/html/magento2/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php on line 93 and 
    defined in /var/www/html/magento2/app/code/Myvendor/Slideshow/Controller/Adminhtml/Slide.php:39

    nStack trace:
    #0 /var/www/html/magento2/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php(93): 
    	Myvendor\\Slideshow\\Controller\\Adminhtml\\Slide->__construct(Object(Magento\\Framework\\ObjectManager\\ObjectManager))
    #1 /var/www/html/magento2/vendor/magento/framework/ObjectManager/Factory/Compiled.php(88): 
    	Magento\\Framework\\ObjectManager\\Factory\\AbstractFactory->createObject('Myvendor\\\\Slidesho...', Array)
    #2 /var/www/html/magento2/vendor/magento/framework/ObjectManager/ObjectManager.php(57): 
    	Magento\\Framework\\ObjectManager\\Factory\\Compiled->create('Myvendor\\\\Slidesho...', Array)
     #3 in /var/www/html/magento2/app/code/Myvendor/Slideshow/Controller/Adminhtml/Slide.php on line 39, 

Myvendor\Slideshow\Controller\Adminhtml\Slide.php:

    namespace Myvendor\Slideshow\Controller\Adminhtml;
 
    use Magento\Backend\App\Action;
    use Magento\Framework\Registry;
    use Magento\Framework\View\Result\PageFactory;
    use Myvendor\Slideshow\Model\SlideFactory;
 
    abstract class Slide extends Action
    {
	/**
	 * Core registry
	 *
	 * @var \Magento\Framework\Registry
	 */
	protected $_coreRegistry;
 
	/**
	 * Result page factory
	 *
	 * @var \Magento\Framework\View\Result\PageFactory
	 */
	protected $_resultPageFactory;
 
	/**
	 * Slide model factory
	 *
	 * @var \Myvendor\Slideshow\Model\SlideFactory
	 */
	protected $_slideFactory;

    /**
	 * @param \Magento\Backend\App\Action\Context $context
	 * @param Registry $coreRegistry
	 * @param PageFactory $resultPageFactory
	 * @param SlideFactory $slideFactory
	 */
	public function __construct(
    \Magento\Backend\App\Action\Context $context,
    Registry $coreRegistry,
    PageFactory $resultPageFactory,
    SlideFactory $slideFactory
    ) 
    {
		parent::__construct($context);
		$this->_coreRegistry = $coreRegistry;
		$this->_resultPageFactory = $resultPageFactory;
		$this->_slideFactory = $slideFactory;
	}

	/**
	 * Slide access rights checking
	 *
	 * @return bool
	 */
	protected function _isAllowed()
	{
		return $this->_authorization->isAllowed('Myvendor_Slideshow::manage_slide');
	}
    }

I am not sure what other classes or xml I need to look at to figure out where this error is coming from. This leaves me rather perplexed right now. I checked the namespaces, they seem all correct. How do I go best about debugging this?

I've cleared var/generation to no effect.