D's greatest mistakes

[Steven Schveighoffer]

On Mon, 29 Nov 2010 13:10:14 -0500, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> On 11/29/10 10:59 AM, Steven Schveighoffer wrote:
>> On Mon, 29 Nov 2010 11:19:29 -0500, Andrei Alexandrescu
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>> Ultimately I believe we need to make Rebindable palatable. That would
>>> have the nice side effect of enabling other proxy types.
>>
>> I think if we get to that point, D will be much more adept at doing a
>> lot of const things (such as ranges of const types).
>>
>> The big hurdle is implicit casting IMO. For example C and
>> Rebindable!(immutable C) needs to implicitly cast to Rebindable!(const
>> C). Right now, builtins and arrays are the only type constructions that
>> enjoy implicit casting to their tail-const counterparts. Until we solve
>> this, any library solution is going to be woefully inadequate.
>
> alias this was meant to solve this problem.

My understanding is that it only works if you already have an instance.   
Will it work for implicit casting from another type?

That is, is it planned to have a function foo:

foo(Rebindable!(const C) c)

callable with a C?

What about a Rebindable!(immutable C)?

-Steve