Multiple alias this, what's the hold up?

[aliak]

On Sunday, 16 June 2019 at 18:25:28 UTC, Jonathan Marler wrote:
> Of course, you could also just make it an error if you have 
> multiple resolutions, which is what I think dmd does with 
> multiple import matches.  In any case, I don't think it matters 
> much as these cases would be fairly uncommon.  If you have a 
> conflict, you can explicitly select one or the other 
> (foo.bar.func() or foo.baz.func()).

That reminded me of private symbols that are publicly aliased. 
Currently this is not possible:

struct S {
   private int a;
   public alias a this;
}

But I vaguely remember talk about implementing this. Tried to 
find a bug report but couldn't. Has there been discussion on 
allowing this or why not to allow it?