how can i use the derive-hierarchy at runtime for typechecking?

[Jarrett Billingsley]

"Chris Nicholson-Sauls" <ibisbasenji at gmail.com> wrote in message 
news:fcv1d1$vp6$1 at digitalmars.com...
>
> Or we could add a new '?.' form for member access that becomes a nop on 
> null references and just use:
> (cast(B) foo)?.doStuff();
>
> Er.......... okay, that's just insane.

What do you think this is, Io?