Description:
------------
I'm not 100% sure this is considered a "bug" as such, anyway, I thought
I'd point it out, and let you decide. It's more a case of the error
message being a little fuzzy.

When trying to assign an item by reference by using the reference
operator, &, to an element inside a class that implements ArrayAccess
produces a werid error message.

Admittedly, the code I've provided is probably not valid PHP code,
because the nature of the ArrayAccess interface means that data is
assigned and returned from offsetSet and offsetGet by value, so using
refernces should probably not work.

However, the when you do try this, you get an error about about post/pre
increment/decrement. I'm not sure what this refers to, but it doesn't
seem to be very descriptive.

Reproduce code:
---------------
<?php

class ArrayAccessImpl implements ArrayAccess {
	private $data = array();

	public function offsetUnset($index) {}

	public function offsetSet($index, $value) {
		$this->data[$index] = $value;
	}

	public function offsetGet($index) {
		return $this->data[$index];
	}

	public function offsetExists($index) {
		return isset($this->data[$index]);
	}
}

$data = new ArrayAccessImpl();
$test = 'some data';
$data['element'] = &$test;

?>

Expected result:
----------------
Unsure, probably an error message relating to the fact ArrayAccess
objects can not assign by reference

Actual result:
--------------
Fatal error: Objects used as arrays in post/pre increment/decrement must
return values by reference

Actually at the moment this is a known issue which we cannot fix
appropriate right away. But we are working on the matter.

I have a similar but different reproduction using two dimensional arrays
instead of explicitly setting a reference.

class ArrayAccessImpl implements ArrayAccess {
  private $data = array();

  public function offsetUnset($index) {}

  public function offsetSet($index, $value) {
    $this->data[$index] = $value;
  }

  public function offsetGet($index) {
    return $this->data[$index];
  }

  public function offsetExists($index) {
    return isset($this->data[$index]);
  }
}

$data = new ArrayAccessImpl();
$data['element'] = array();
$data['element']['element2'] = "hi";

Thank you for your bug report. This issue has already been fixed
in the latest released version of PHP, which you can download at 
http://www.php.net/downloads.php

We found out that this is not solvable without blowing up the interface
and creating a BC or providing an additional interface to support
references and thereby creating an internal nightmare - actually i don't
see a way we can make that work ever. Thus we decided to enforce the
original design and disallow references completley. Also the error
message should have changed with 5.0.4 or is being changed with
5.0.5/5.1 at least