extend foreach to work on non-arrays

[aliak]

On Thursday, 24 May 2018 at 23:28:59 UTC, IntegratedDimensions 
wrote:
> cool, and this is optimal, right? non-arrays are not converted 
> in to arrays, etc?

Seems they are not converted no, but it loops like an extra 
variable is stored though (a bool to denote existence of a value)

https://github.com/dlang/phobos/blob/v2.080.0/std/range/package.d#L9512