error[E0635]: unknown feature stdsimd

[ArunGust]

unknown feature stdsimd : Got below after updating rust to new version rustc 1.78.0-nightly (f067fd608 2024-02-05)

error[E0635]: unknown feature stdsimd
--> C:\SYSTEM\RUST\CARGO\registry\src\index.crates.io-6f17d22bba15001f\ahash-0.7.7\src/lib.rs:33:42
|
33 | #![cfg_attr(feature = "stdsimd", feature(stdsimd))]
| ^^^^^^^

For more information about this error, try rustc --explain E0635.
error: could not compile ahash (lib) due to 1 previous error

[tusharmath]

Facing similar issue.

[tmpfs]

Same here on version 0.7.7, it's broken my crate's documentation build on docs.rs but works fine for me locally on Linux and MacOS, not sure why it's only broken in the docs.rs sandbox environment.

Here is the build log:

https://docs.rs/crate/sos-sdk/0.10.0/builds/1116456

[Kobzol]

This is caused by rust-lang/rust#117372. This problem in ahash was already fixed in #183, which was released in 0.8.7 (it just isn't visible as a GitHub release).

[RalfJung]

Fundamentally this is caused by logic in build.rs that auto-enables a nightly feature when it detects that it is built with a nightly rustc. Such logic is fragile and prone to errors as nightly features evolve before stabilization.

Crates should never automatically enable nightly features, this should generally be opt-in. If they try to do it automatically they need to be very careful and account for the fact that nightly features are not stable, and might look very different in future nightly versions.

I see aHash still does the same kind of auto-detection with the specialize feature. That's a similar issue just waiting to happen.

[humb1t]

Same for me

[mina86]

If you’re on 0.8 branch → update to 0.8.7. See #188.

However, I’m also picking up dependency on 0.7.7 through chain of older dependencies (borsh 0.9 → hashbrown 0.11 → ahash 0.7) which I can’t easily get rid of on my side. It’d be fantastic if we could get backport to 0.7 branch as well. I’ve commented that in #188.

[Kobzol]

It seems that a lot of stuff depends on ahash < 0.8. It would be indeed useful if it was possible to put out a backported patch release for 0.7.

[vikingSec]

Seems like this is breaking trunk and leptos

I was just trying to get into learning leptos, so installing all of the right versions according to the docs and trying to install trunk and cargo-leptos both runs into this bug.

Console output:

> cargo install trunk
error[E0635]: unknown feature `stdsimd`
  --> /Users/medwards/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ahash-0.7.7/src/lib.rs:33:42
   |
33 | #![cfg_attr(feature = "stdsimd", feature(stdsimd))]
   |                                          ^^^^^^^

For more information about this error, try `rustc --explain E0635`.
error: could not compile `ahash` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: failed to compile `trunk v0.18.7`, intermediate artifacts can be found at `/var/folders/9f/w50rg2wj193fh6jv5rt0lk1r0000gn/T/cargo-installif2CRL`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_TARGET_DIR` to that path. 

Not trying to brigade the comments, I'd work on a fix but you probably don't want a Rust noop running around your repo.