Walter Bright Wrote:

> Unshared can be implicitly cast to shared, so you shouldn't have to.

That should not be implicit.

For one, thread-local garbage collection of non-shared data would leave dangling references to garbage memory.

Two, the guarantees for shared data are lost. Code using the non-shared reference will not respect that the variable really is shared.

Jason House wrote:
> Walter Bright Wrote:
> 
>> Unshared can be implicitly cast to shared, so you shouldn't have
>> to.
> 
> That should not be implicit.
> 
> For one, thread-local garbage collection of non-shared data would
> leave dangling references to garbage memory.

True, but the memory allocation system shouldn't be (and isn't) built that way.


> Two, the guarantees for shared data are lost. Code using the
> non-shared reference will not respect that the variable really is
> shared.

That would be true if shared were implicitly cast to unshared, but that's not the case. It's unshared implicitly cast to shared.