Deprecate implicit conversion between signed and unsigned integers

[Nick Treleaven]

On Monday, 13 May 2024 at 12:48:04 UTC, Dukc wrote:
> Paul Backus kirjoitti 12.5.2024 klo 16.32:
> Ditching all backwards-compatibility issues, it would be a good 
> idea. But, this would cause *tremendous* amounts of breakage.
>
> Before, I would have said it simply isn't worth it. But since 
> we're going to have editions, maybe. I'm still somewhat 
> sceptical though. Nothing will break without a warning and 
> people can stay at older editions if they want, but it's going 
> to add a lot of work for someone migrating 100_000 lines to a 
> new edition. That amount of code will likely have hundreds or 
> even thousands of deprecations to fix.

I think even with editions we need to avoid making it hard to 
port code to a newer edition. So instead of a deprecation, we 
could make it a `-w` warning instead.

> I tend to think that if we will write an official automatic 
> tool to add the needed casts, it's probably worth it. Otherwise 
> not.