An important pull request: accessing shared affix for immutable data

[Iakh via Digitalmars-d]

On Friday, 12 February 2016 at 19:12:48 UTC, Andrei Alexandrescu 
wrote:
> https://github.com/D-Programming-Language/phobos/pull/3991
>
> A short while ago Dicebot discussed the notion of using the 
> allocator to store the reference count of objects (and 
> generally metadata). The allocator seems to be a good place 
> because in a way it's a source of "ground truth" - no matter 
> how data is qualified, it originated as untyped mutable bytes 
> from the allocator.
> [...]
>
> Destroy!
>
> Andrei

So you can use metadata only with global allocators,
until you don't need to save ref to the allocator.

Why can't we use attribute @intransitive on ref fields to prevents
immutable being transitively applied on referred content?
Add some restrictions (only private, wrap using with trusted) and
it would be enough to implement RefCounting with immutable.