Foreach loops on static arrays error message

[Nemanja Boric via Digitalmars-d]

On Thursday, 6 July 2017 at 08:49:33 UTC, Stefan Koch wrote:
> On Thursday, 6 July 2017 at 08:26:42 UTC, Guillaume Chatelet 
> wrote:
>>> [...]
>
> I'd say this is not often encoutered.
> One should avoid using a different type then size_t for the 
> index, as it can have negative performance implications.

Interesting. What would be the example of negative performance 
implication? I'm guilty of using the int on occasions.