`in` parameters made useful

[Atila Neves]

On Friday, 31 July 2020 at 21:49:25 UTC, Mathias LANG wrote:
> Hi everyone,
> For a long time I've been pretty annoyed by the state of `in` 
> parameters.
> In case it needs any clarification, I'm talking at what's 
> between the asterisks (*) here: `void foo (*in* char[] arg)`).
>
> [...]

I think that having `in ref` is preferable than introducing new 
rules. Everything else makes sense to me, but it's possible I'm 
missing something.