In a class I often use functions like this to get/set variables:
class example {
  var $somevar;
function Somevar($arg = NULL) {
  if (!is_null($arg))
    $this->somevar = $arg;
return $this->somevar;
}
}

Everything is ok, but sometimes I would like to be able to do the same
with references, like so:
class example2 {
  var $someobject;
function &Someobject(&$arg = NULL) {
  if (!is_null($arg))
    $this->someobject = &$arg;
return $this->someobject;
}
}

The second example will throw an parse error, expecting ) after &$arg.

I suppose this isn't an bug, but rather something not implemented or is intensional.