Immutable Message Passing

[Jonathan M Davis]

On Sunday, December 04, 2011 01:24:02 Andrew Wiley wrote:
> This should work, right? I'm not just going crazy or something?
> 
> import std.concurrency;
> import std.stdio;
> 
> class Bob {
> }
> 
> void main() {
>     auto tid = spawn(&b);
>     tid.send(new immutable(Bob)());
> }
> 
> void b() {
>     receive(
>         (immutable(Bob) b) {
>             writeln("got it");
>         }
>     );
> }
> 
> 
> I'm getting this from both GDC (trunk) and DMD (2.056 and trunk - I
> can't seem to get 2.055 to run):
> core.exception.AssertError@/usr/include/d/std/variant.d(286): immutable(Bob)
> 
> Seems like some type conversion isn't working properly and variant is
> flagging immutable types as not assignable?

Well, that particular assertion seems to be because of the immutability. It 
seems that Variant can't handle it - the comment with it being

// type is not assignable

But I'd have to go digging to see why on earth this is failing (and that's 
assuming that it's not a compiler bug, since then it would be completely out 
of my league). It _looks_ like it should work.

- Jonathan M Davis