why $ is need to access array [negative index]?

[mw]

On Friday, 18 September 2020 at 20:06:01 UTC, Steven 
Schveighoffer wrote:
>
> I would say no. The indexing code lowers to a machine 
> instruction. Making it so a negative value means something else 
> means every single indexing operation is going to have to check 
> whether it's negative, and if so do something completely 
> different.

Currently we have range check on every single indexing operation 
already; so the trade-off here is: adding one more check v.s. the 
convenience it buys.

>
> You can create your own array type if you want this behavior.