<?php
function f(Osoba $o){
$o->programuj();
}
class Osoba {
protected $pesel;
public function __construct($pesel){
$this-> pesel = $pesel;
}
public function getPesel(){
return $this -> pesel;
}
}
class Programista extends Osoba{
public function programuj(){
}
}
$p = new Programista(76021011673); // fatal error
f($p);