[PATCH v9 4/6] rust: enable `clippy::as_underscore` lint

[Miguel Ojeda]

On Fri, Apr 18, 2025 at 5:09 PM Boqun Feng <boqun.feng at gmail.com> wrote:
>
> I'm leaning towards to 2 and then 3, because using `as` can sometimes
> surprise you when you change the type. Thoughts?

Having explicit functions sounds good to me, and would also help
migrating later easily to anything else (because all cases are
explicitly tagged and easy to grep for).

Cheers,
Miguel