Alias syntax removal

[Michael]

> Why I argue that the syntax `alias this = sym;` is wrong? 
> Because:
>
> 1. A normal alias declaration (creating aliased name for 
> existing symbol)
> and alias this feature
> (making a *subtyped* struct through implicit access to its 
> field) are
> entirely different and has distinct semantics.
> They merely share a keyword 'alias'.
>
> 2. Instead, we can have much more consistent, useful, and 
> scalable syntax.
> At the same time, I proposed a new syntax `alias this : ident;` 
> for alias
> this feature.
> https://github.com/D-Programming-Language/d-programming-language.org/pull/200
>
> struct S {
>     int value;
>     alias this : value;   // proposed syntax
> }
>
> Benefits of the proposed syntax are:
> 2a. It is consistent with class inheritance syntax `class C : B 
> {}`.
> 2b. It is scalable for multiple alias this feature, as like 
> `alias this
> : sym1, sym2, ...;` .
>
> If D community highly require the syntax `alias this = sym`, 
> I'll agree to
> adding it again.
> But for that, we should discuss about its cost and benefit.
>
> Sorry for my poor writing.
> Regards.
>
> Kenji Hara

http://forum.dlang.org/thread/aaflopktcjmljxdnoizj@forum.dlang.org
http://d.puremagic.com/issues/show_bug.cgi?id=9569