Shared and GC

[Peter Alexander via Digitalmars-d-learn]

On Thursday, 15 January 2015 at 15:24:55 UTC, Ola Fosheim Grøstad 
wrote:
> I am trying to understand the idea behind "shared" typing fully.
>
> If I am only allowed to share objects with another thread if it 
> is typed "shared", doesn't that imply that it should be 
> allocated as shared too and only be allowed to contain pointers 
> to "shared"?

Yes, shared is transitive.

struct S { int* p; }
void main() {
	S s1;
	shared S s2 = s1;  // error, but ok if p is int.
}


> That would be nice, because then a precise garbage collector 
> could choose between local collection scans and global 
> collection scans.

I think something like this is part of the plan, but shared 
semantics are still up in the air.