Description:
------------
Extending PDOStatement and replacing fetch() doesn't work when iterating using foreach. It calls the built in fetch rather than my overridden one. This can be circumvented using while($r = $s->fetch()) { .. } but I believe this behaviour is unexpected.

Test script:
---------------
class ExtendedStatement extends PDOStatement {
	protected function __construct() {
		$this->setFetchMode(PDO::FETCH_ASSOC);
	}
	public function fetch($fetch_style = PDO::FETCH_ASSOC, $cursor_orientation = PDO::FETCH_ORI_NEXT, $cursor_offset = 0)
	{
		$r = parent::fetch($fetch_style, $cursor_orientation, $cursor_offset);
		if (is_array($r)) { $r["extradata"] = TRUE; }
		return $r;
	}
}
$db = new PDO("sqlite::memory:");
$db->setAttribute(PDO::ATTR_STATEMENT_CLASS, array("ExtendedStatement", array($db)));
$db->exec("CREATE TABLE example(id INTEGER PRIMARY KEY, name VARCHAR)");
$db->exec("INSERT INTO example(name) VALUES('test')");
$s = $db->prepare("SELECT * FROM example");
$s->execute();
foreach ($s as $r) {
	var_dump($r);
}

Expected result:
----------------
array(3) {
  ["id"]=>
  string(1) "1"
  ["name"]=>
  string(4) "test"
  ["extradata"]=>
  bool(true)
}

Actual result:
--------------
array(2) {
  ["id"]=>
  string(1) "1"
  ["name"]=>
  string(4) "test"
}