Reimplementing the bulk of std.meta iteratively

[Adam D. Ruppe]

On Tuesday, 29 September 2020 at 14:07:14 UTC, Andrei 
Alexandrescu wrote:
> As things are now, AAs don't quite behave like any other things.

The biggest difference I see is how null works, the keyword.

void foo(string[string] aa) {}

foo(null); // works.

But that's outright impossible with a library struct.

yes, I'm bringing up my wish for implicit construction again :P