Re: [PATCH v1] rust: bug: prevent dead_code warning from warn_on!'s flags constant

On Sat, 8 Aug 2026 20:19:25 +0200
Miguel Ojeda <[email protected]> wrote:

> On Fri, Jul 24, 2026 at 1:40 AM Gary Guo <[email protected]> wrote:
>>
>> Also, the proper fix would be to mark it as used in the `warn_flags` macro
>> that discard the expression.
>>
>>     if false {
>>         _ = $flags;
>>     }
> 
> Maybe it could be nice to have a `discard!` macro later on.

Looks like declare_trace! in rust/kernel/tracepoint.rs does the same
thing so I think it is worth having as a standalone macro.

Since it marks the expressions as used without evaluating them, how
about `mark_used!`?

I will send a patch once this lands.