abs and minimum values

[kyle]

On Thursday, 28 October 2021 at 21:23:15 UTC, kyle wrote:
> ```
> void main()
> {
>     import std.math : abs, sgn;
>
>     alias n_type = short; //or int, long, byte, whatever
>
>     assert(n_type.min == abs(n_type.min));
>     assert(sgn(abs(n_type.min)) == -1);
> }
> ```
> I stumbled into this fun today. I understand why abs yields a 
> negative value here with overflow and no promotion. I just want 
> to know if it should. Should abs ever return a negative number? 
> Thanks.

Okay I checked the phobos docs and it does say "Limitations
Does not work correctly for signed intergal types and value 
Num.min." Should have looked there first, I know. Still seems 
pretty silly.