what exactly does cast(shared) and cast away shared do?

[Kagamin]

On Tuesday, 16 June 2020 at 07:22:59 UTC, mw wrote:
> `shared` or not is purely a compile-time attribute, not some 
> runtime dynamic attribute on the object, i.e. at runtime when 
> you get hold of an object on the heap, there's no way you can 
> tell from the object itself whether it's shared or not.

The way to tell it is if the object is typed as shared, then it's 
shared, if it's not typed as shared, then it's not shared. The 
only way to circumvent this is to use a cast, that circumvents 
entire type system.