Description:
------------
It's seems there is not correctly processed exception from current() and script ends up with fatal error.

Reproduce code:
---------------
class Test implements Iterator {

    public $arr = array();

    public function rewind()    { return reset($this->arr); }
    public function current()   { throw new Exception(); }
    public function key()       { return key($this->arr); }
    public function next()      { return next($this->arr); }
    public function valid()     { return (current($this->arr) !== false); }
}

$t = new Test();
$t->arr =  array(1, 2, 3);

try {
    foreach ($t as $v) {
        ; // do something
    }
} catch (Exception $e) {
    ; // handle exception
}


Actual result:
--------------
Fatal error: Couldn't execute method Test::key in Unknown on line 0