PHP 7.3 vs 7.4

In PHP 7.3, you can use type declarations in functions:

abstract class Controller {

    protected $registry;

    protected $customer,

    public function __construct(Registry $registry) {

        $this->registry = $registry;

    }

    public function getCustomer(): Customer {

        return $customer;

    }

But type declaration for the properties will cause errors like "Parse error: syntax error, unexpected 'Registry' (T_STRING), expecting function (T_FUNCTION) or const (T_CONST)":

    protected Registry $registry;

    protected Customer $customer;

Typed properties was introduced in PHP 7.4.