"unused manifest key" warning occurs upon cargo check

[gretchenfrage]

Running the main branch (commit 08ee9ee471b61fe2c7a7248dfb628b0edcf6aca9) with the latest cargo version (cargo 1.81.0 (2dbb1af80 2024-08-20), rustc 1.81.0 (eeb90cda1 2024-09-04)) emits the following warning:

warning: /home/phoenix/repos/quinn/quinn-udp/Cargo.toml: unused manifest key: target.cfg(any(target_os = "linux", target_os = "windows")).bench

[djc]

I've also seen this, but not sure what to do about it. Cargo.toml context:

https://github.com/quinn-rs/quinn/blob/main/quinn-udp/Cargo.toml#L35

throughput benchmark using Criterion:

https://github.com/quinn-rs/quinn/blob/main/quinn-udp/benches/throughput.rs

(Asked t-cargo for suggestions on Zulip: https://rust-lang.zulipchat.com/#narrow/stream/246057-t-cargo/topic/.22unused.20manifest.20key.22.)

[mxinden]

Might be resolved through #2010 which fixes the invalid cfg.

I introduced this in #1915. Sorry about that.