https://crates.io/crates/serde_derive has since v1.0.172, July 10, shipped a pre-compiled binary for Linux x64, which it uses to reduce compile times for users of this crate.
As this was a patch release, it has mostly gone under the radar. https://github.com/serde-rs/serde/issues/2538 was raised July 28 and closed August 17 as effectively wontfix, and the issue is now locked.
There are two PRs to make this feature optional:
- Add derive_compiled feature to force compilation of serde_derive by sagudev · Pull Request #2579 · serde-rs/serde · GitHub
- Provide opt-out `feature=from_source` to use `serde_derive` source by pinkforest · Pull Request #2580 · serde-rs/serde · GitHub
This is filed under announcements as in the current state, some users in regulated industries (Automotive, Medicine, etc) will need to do additional work to document this precompiled binary as a separate dependency that is being injected into the Rust compilation phase.