when is a GDC/D2/Phobos bug a GDC bug?

[Trass3r]

> I've played with the new GDC version today. Overall it seems solid, but
> I've encountered some issues that are probably Phobos-related. Since
> this is my first 64-bit D compiler, I wonder whether some parts of
> Phobos might not yet be 64-bit ready.

I'm pretty sure there are certain corner cases.
This is a tiny one:
http://d.puremagic.com/issues/show_bug.cgi?id=4310