Manu's `shared` vs the @trusted promise

[Kagamin]

On Sunday, 21 October 2018 at 22:03:00 UTC, ag0aep6g wrote:
> With Manu's `shared`, there is implicit conversion from 
> non-`shared` to `shared`. It would essentially become a 
> language rule. For that rule to be sound, any access to 
> `shared` data must be @system. And more challengingly, 
> @system/@trusted code must be written carefully with the new 
> rule in mind.

Well, we have __gshared for that. When code is written carefully, 
it works fine, C, C# and Java do well that way, you just 
architecturally minimize amount of multithreaded code, and it 
becomes manageable, for an example see 
https://github.com/dlang/druntime/blob/master/src/core/sync/semaphore.d