What's the deal with the massive duplication in std.meta?

[Paul Backus]

On Tuesday, 4 May 2021 at 17:39:54 UTC, Q. Schroll wrote:
> On Tuesday, 4 May 2021 at 16:54:13 UTC, Andrei Alexandrescu 
> wrote:
>> I put together a bunch other related pull requests:
>>
>> https://github.com/dlang/phobos/pulls/andralex
>>
>> Using alias assignment with good measure leads to much simpler 
>> and clearer code. I also measured memory consumption 
>> improvements, but for the Phobos unittest they are not 
>> dramatic.
>
> Is there some resource where the rules for alias assignments 
> are spelled out? Googling '"alias assignment" site:dlang.org' 
> produces no meaningful results. Having procedural aspects in a 
> declarative space looks a bit odd to me. The change logs 
> revealed nothing.

There's an open spec PR:

https://github.com/dlang/dlang.org/pull/2919