Sealed classes - would you want them in D?

[KingJoffrey]

On Monday, 14 May 2018 at 07:59:06 UTC, Jonathan M Davis wrote:
> .. In addition, we rely on function encapsulation for Voldemort 
> types...

Actually, we rely on encapsulation (boundaries) for a lot more 
than that.

How do we get from the orange room to the blue room, if there is 
no boundary?

https://www.youtube.com/watch?v=IP5akjPwqEA

(great quote at the end btw - but watch the whole thing first - 
it'll make more sense)