Want reasonable reference counting? Disable automatic sharing of immutable

[Stanislav Blinov]

On Saturday, 13 November 2021 at 03:03:21 UTC, Steven 
Schveighoffer wrote:

> This is an odd way to look at it. The finalizers are not run 
> directly, and maybe not even run on the same thread as the pure 
> function being run. They also should not be observable (for the 
> most part), because you should not have access to that data any 
> more.
>
> It's like saying an OS context switch that happens in the 
> middle of a pure function must somehow be valid pure code.
>
> -Steve

Not run directly??? As far as I know, GC, on allocation, may 
hijack the caller to do a collection. Net effect is that it 
executes arbitrary (not pure, not @safe, etc.) code within 
caller. Caller is marked pure. GC may run impure finalizers that 
mutate some global state. Something as stupid as call to "close" 
which may set errno, or, I don't know, freeing half of program 
state, mutating shared globals... There can be no "for the most 
part" here. You've got pure function mutating global state. 
That's something pure functions aren't supposed to be doing.
Unless that changed and GC isn't doing that anymore, that's a bug 
that's been open for some years now.