On Mon, Oct 15, 2018 at 1:15 PM Stanislav Blinov via Digitalmars-d <digitalmars-d@puremagic.com> wrote: > > On Monday, 15 October 2018 at 18:46:45 UTC, Manu wrote: > > > Assuming the rules above: "can't read or write to members", and > > the understanding that `shared` methods are expected to have > > threadsafe implementations (because that's the whole point), > > what are the risks from allowing T* -> shared(T)* conversion? > > > > All the risks that I think have been identified previously > > assume that you can arbitrarily modify the data. That's > > insanity... assume we fix that... I think the promotion > > actually becomes safe now...? > > You're still talking about implicit promotion?
Absolutely. This is critical to make shared useful, and I think there's a path to make it work. > No, it does not > become safe no matter what restrictions you put on `shared` > instances, because the caller of any function that takes `shared` > arguments remains blissfully unaware of this promotion. It doesn't matter... what danger is there of distributing a shared pointer? Are you concerned that someone with a shared reference might call a threadsafe method? If that's an invalid operation, then the method has broken it's basic agreed contract. And I agree that it's conceivable that you could contrive a bad program, but you can contrive a bad program with literally any language feature!
