Multiple alias this, what's the hold up?

[Jonathan M Davis]

On Wednesday, June 19, 2019 1:29:40 AM MDT Les De Ridder via Digitalmars-d 
wrote:
> On Tuesday, 18 June 2019 at 22:51:51 UTC, Jonathan M Davis wrote:
> > [...]
> >
> > I expect that it's perfectly safe to remove mentioning multiple
> > alias this-es from your book and that it would give a far more
> > accurate representation of the state of D. Acting like it's
> > just a matter of time before multiple alias this-es get added
> > to D would be giving folks the wrong idea with how things
> > stand. And if someone actually comes up with a proposal that
> > convinces Walter, it's not like it would be hard to grab what
> > you had and re-add it with any necessary changes (at least if
> > you have your book in source control like I would think you
> > would).
> >
> > [...]
>
> If that's indeed the case it should probably be removed from the
> spec[1] as well.
>
> [1] https://dlang.org/spec/class.html#alias-this (subsection 7)

IMHO, regardless of whether we intend to add the ability to have multiple
alias this-es, the spec really shouldn't say that they're a thing when
they're not actually implemented - even if it then follows that up by saying
that they're not currently implemented like it does right now.

- Jonathan M Davis