Regarding foreach loop index ranges

[Steven Schveighoffer via Digitalmars-d-learn]

On Mon, 21 Apr 2014 07:49:03 -0400, bearophile <bearophileHUGS at lycos.com>  
wrote:

> In this case I am not sure about bug reports, so I ask here.
>
> In this program the first loop doesn't compile, giving a nice error:
>
> test.d(3,5): Error: index type 'ubyte' cannot cover index range 0..300
>
> If you comment out the first loop, the second compiles and runs, but it  
> seems to go in an infinite loop:
>
>
> void main() {
>      int[300] data;
>      foreach (ubyte i, x; data)   {} // Error
>      foreach (ubyte i, x; data[]) {} // compiles
> }
>
>
> For the second loop one possible alternative behavour is to refuse a  
> ubyte index and accept only a size_t index if it loops on a dynamic  
> array.
> Another alternative is: the i variable can go from 0 to 255, then go up  
> to the modulus of the remaining indexes, and then stop.

A third option is allow the code to compile, but throw an assert in  
non-release mode when the foreach statement is encountered "ubyte cannot  
process all indexes of data."

This would be the least code-breaking option that saves a bug (you don't  
know that the code can handle modulo indexes).

Then you could deprecate to disallowing ubyte indexes.

-Steve