<?php

class foo2 {
    const BAR = 'foobar';
}

class foo extends foo2 {
    const BAR = "foo's bar";

    function test($a = self::BAR) {
    }

    function test2($a = parent::BAR) {
    }

    function test3($a = foo::BAR) {
    }

    function test4($a = foo2::BAR) {
    }
}

echo new ReflectionObject(new foo);

?>