Method overriding of abstract class that implements an interface

Question

My question might be a bit lame. I can't really understand how abstract class method overriding works. In the code bellow I have OrderController with method that accepts Order model which derives from Model class itself, why does it throw the error?

interface CrudInterface
{
    public function show(Model $model);
}

abstract class CrudController extends Controller implements CrudInterface {
    public function show(Model $model)
    {
        return $model;
    }
}

class OrderController extends CrudController {

    // Throws an erorr ("
    // Declaration of App\Http\Controllers\OrderController::show(App\Order $order) should be compatible with 
    // App\Http\Controllers\CrudController::show(Illuminate\Database\Eloquent\Model $model
    // ")
    public function show (Order $order) {
        return $order
    }

}

Thanks in advance.

Answer 1

Interface should match:

class OrderController extends CrudController {

    public function show (Model $order) {
        if (!$order instanceOf Order) {
           throw new InvalidArgumentException();
        }
        return $order
    }
}