Sharing in D

[Walter Bright]

superdan wrote:
> makes sense. but i guess we agree that that is the rare case in which
> you're ok with a race. the usual case is you don't want a race. so i
> think it's fair that the rare case requires a cast. walt seems to
> have gotten the default right as far as i can tell.

It's not just me. There are several people who've been hammering away at 
how this needs to work, including Andrei, Bartosz, David Held, Brad 
Roberts, and Eric Niebler.