std.typecons.Ref(T).opImplicitCastTo()

[Jonathan M Davis]

On Monday, April 02, 2012 05:41:00 Alex Rønne Petersen wrote:
> On 30-03-2012 19:28, Jonathan M Davis wrote:
> > On Friday, March 30, 2012 16:27:44 simendsjo wrote:
> >> Is opImplicitCastTo a planned feature?
> >> It's only used in this type as I can see, and it doesn't add implicit
> >> casting.
> > 
> > It's been discussed, but I don't think that it's ever been agreed upon. In
> > theory, alias this is meant to deal with implicit casts. I don't know whay
> > anything in Phobos would have such a function. And I don't know what the
> > point of std.typecons.Ref really is. It's undocumented (and clearly is
> > _intended_ to be undocumented given what the comment is started with). I
> > suspect that it's an old idea that just hasn't been cleaned out. If
> > you'll notice, it also has opDot, which is being removed from the
> > language.
> > 
> > - Jonathan M Davis
> 
> But you can only have one alias this per type. It is outright
> incompatible with the idea of implicit cast operators. It's like
> restricting opCast to only one overload per function - a
> not-very-pragmatic decision if you ask me...

alias this is not supposed to be restricted such that you can only have one 
per type. That's a temporary, implementation problem. TDPL specifically talks 
about having multiple alias thises per type.

- Jonathan M Davis