Unstable feature is used when checking coverage in upstream crate

[Kjetil Kjeka]

We have recently introduced a transitive dependency on calloop for one of our crates we test coverage for.

After introducing this dependency we cannot use the stable compiler to test for coverage due to the error message.

error[E0554]: `#![feature]` may not be used on the stable release channel
   --> /root/.cargo/registry/src/github.com-1ecc6299db9ec823/calloop-0.10.3/src/lib.rs:146:23
    |
146 | #![cfg_attr(coverage, feature(no_coverage))]
    |                       ^^^^^^^^^^^^^^^^^^^^

I assume this feature exists for testing the coverage of calloop itself, and there are not much reason to use it when calloop is used as a dependency?

Would it be acceptable to make a similar solution where features are not enabled for upstream crates? For instance by creating a feature on the crate itself?

[Elinor B.]

Ah yeah, I didn't anticipate this issue, that's unfortunate. Indeed moving to a cargo feature is certainly the right thing to do.