Using xdebug 2.0.2, PHP 5.2.8 with no other extensions loaded.

Expected Behavior:

$ php -n test.php

Fatal error: Call to undefined function hasChildren() in /home/kminkler/test.php on line 31

Current Behavior:

$ php test.php
Segmentation fault

Running Program:

$ cat test.php
<?php

class A_Iterator implements RecursiveIterator
{
private $a = NULL;
private $a_children = NULL;
public function __construct(A $a) { $this->a = $a; $this->a_children = $a->getChildren(); }
// Iterator
public function rewind() { $this->a_children->rewind(); }
public function valid() { return $this->a_children->valid(); }
public function current() { return $this->a_children->current(); }
public function key() { return $this->a_children->key(); }
public function next() { $this->a_children->next(); }
// RecursiveIterator
public function hasChildren() { return $this->current()->hasChildren(); }
public function getChildren() { return new A_Iterator($this->current()); }
}

class A implements IteratorAggregate
{
private $b = array();
public function __construct(array $b) { $this->b = $b; }
// IteratorAggregate
public function getIterator() { return new A_Iterator($this); }

    // Non-Iterator methods
    public function hasChildren() { return count($this->b) > 0; }
    public function getChildren()
    {
            // segmentation fault on next line!
            if (!hasChildren())
            {
                    return new EmptyIterator();
            }

            return new ArrayIterator($this->b);
    }

}

$a = new A(array(new A(array()), new A(array())));

$iterator = new RecursiveIteratorIterator($a);
foreach ($a as $key => $value) { }