[bnr]

The issue only occurs when the locale is changed between registering and looking up the class.

[pieter]

Doesn't look like that from the bug report; there the locale is set first, then the class is defined and then looked up.

[bnr]

PHP registers classes (and functions) at parse time, not at execution time.

i.e. this will print "bar":

    <?php
    echo foo();
    function foo() { return "bar"; }