Deprecation: foreach: loop index implicitly converted from size_t to int

[BoQsc]

On Friday, 3 May 2024 at 13:18:02 UTC, user1234 wrote:
> On Friday, 3 May 2024 at 10:50:03 UTC, BoQsc wrote:
>> Why am I forced to visit this D Lang thread, why this 
>> deprecation warning still appears in my console window in the 
>> latest version of DMD. Does not make any sense from the 
>> developer's perspective to show this warning and pollute the 
>> already polluted logging entries of the compiler. How am I 
>> suppose to program anything effectively if half of the screen 
>> are some nonsensical deprecation warnings without guidance or 
>> sane explanations.
>>
>> This is not better
>> ```
>>     foreach (i, row; arr)
>> ```
>> than
>> ```
>>     foreach (int i, row; arr)
>> ```
>> Hides the datatype and makes the D language appear in-explicit 
>> and annoying.
>>
>> What is this language becoming. A completely weak typed 
>> language or something?
>>
>> I would use JavaScript if I would want that. How are we 
>> suppose to make whole sane Operating Systems with such 
>> syntaxes. Do everyone just enjoy having bugs with some 
>> implicit size_t, or do everyone just enjoy deprecation 
>> warnings in their logging systems when there are way more 
>> important problems to solve, that are actually project related.
>
> **You can specify the index type, just choose the right one.** 
> For now there's a deprecation message but after some while 
> you'll get a proper error message, e.g _"index type for arr 
> must be of type T because arr.length type is T"_.
>
> What's is happening now is to help people updating their code 
> and prevent abrupt breakages.




So how would you update this example, what is the right index 
type here to choose?

```
import std.stdio : writefln;

void main() {
     auto arr = [
         [5, 15],      // 20
         [2, 3, 2, 3], // 10
         [3, 6, 2, 9], // 20
     ];

     foreach (i, row; arr)
     {
         double total = 0.0;
         foreach (e; row)
             total += e;

         auto avg = total / row.length;
         writefln("AVG [row=%d]: %.2f", i, avg);
     }
}
```

Example taken from https://tour.dlang.org/tour/en/basics/foreach