Very limited shared promotion

[Kagamin]

On Friday, 21 June 2019 at 12:07:06 UTC, Manu wrote:
> There is no "between threads" unless you have already entered 
> @trusted land.

@trusted doesn't break the guarantees advertized by the type 
system; when it does, it's a bug that should be fixed (in code, 
not in language). It's only the compiler is not smart enough to 
verify that @trusted code uphold the type system.