why run cargo bench only using nightly?

[florianjacob]

The readme says:

automatically only run cargo bench when supported (nightly compiler)

Is that still true? cargo bench seemed to work just fine with stable rust (1.6). Are there any other reasons why cargo bench should run only on nightly?

The current behaviour causes issues like olivedae/harald#7 and needs workarounds like #33.

[huonw]

The test crate and hence the test::Bencher type needed from it for benchmarks are unstable, and hence can only be used with a nightly compiler. (Note the automatic unstable feature passing is somewhat orthogonal to this: one can place benchmarks externally in benches/*.rs and hence benchmarks don't need #[cfg(feature = "...")] at all.)

[huonw]

For the feature passing, see, for instance, #5, or the end of the Example section of the README.

[florianjacob]

Ok, now I understand, thanks for your time. 😄