PHP Version: 8.2.17

It works:

class Request {}

class FormRequest extends Request {}

function test(Request $request) {
    print_r('buuu!' . get_class($request));
}

test(new FormRequest());

Result:

buuu!FormRequest

It does not work:

class Request {}

class FormRequest extends Request {}

class Animal {
    public function test(Request $request) {}
}

class Giraffe extends Animal {
    public function test(FormRequest $request) {
        print_r('buuu!' . get_class($request));
    }
}

(new Giraffe())->test(new FormRequest());

Result:

Fatal error: Declaration of Giraffe::test(FormRequest $request) must be compatible with Animal::test(Request $request) in /home/user/scripts/code.php on line 14

Now the question arises: WHAT IS THE DIFFERENCE BEYOND POO?