[PATCH] rust: bug: fix `dead_code` warning in `warn_on!`

[Gary Guo]

On Sat Aug 8, 2026 at 12:21 AM BST, Miguel Ojeda wrote:
> On Sat, Aug 8, 2026 at 12:43 AM FUJITA Tomonori <tomo at flapping.org> wrote:
>>
>> I sent a fix for this bug a few days ago:
>>
>> https://lore.kernel.org/all/20260801024841.786664-1-tomo@flapping.org/
>
> Ah, right, sorry! I also saw another one with `rusttest` for arm64 and
> riscv64. Did you see that one? We probably need a `cfg(testlib)`
> split.

I am not sure how much value does `rusttest` still provide, given that KUnit can
test much more stuff in an actual envirionment. The fact that we have to do
special casing does suggest to me that we might want to remove it.

Best,
Gary