extend foreach to work on non-arrays

[meppl]

On Thursday, 24 May 2018 at 22:43:00 UTC, IntegratedDimensions 
wrote:
> Doesn't make any sense?
>
> foreach(a; x)
>
> if x is not an array then a = x and the loop reduces simply and 
> function to the case it is not so their can be no harm.
>
> It unifies the concepts so that one does not have to worry if x 
> is an array or not and can offer no harm since when x is not an 
> array everything simply reduces to an an alias of x.

on the otherhand some programmer might want to get informed buy 
an error-msg, if he accidentally used a non-iteratable variable 
for `foreach`-iteration. To avoid a silent bug