Hi Danny, > How does rustc find the (Rust) dependencies when building a package in > cargo-build-system?
You should be able to override the default rust or cargo version by passing #:rustc or/and #:cargo as arguments to the build-system. See guix/build-system/cargo.scm. > I read that there are actual Rust binary libraries, seldomly used, and > everything-included-only-as-source otherwise. How do I specify which it is? By actual Rust binary library I assume you mean a library with a C ABI that can be dynamically linked against, written in rust. A library like that should or would contain a Cargo.lock file nailing down all the crate versions required, making sure that the project can be built using the same rustc and cargo versions. With a Cargo.lock file present the only remaining issue is figuring out whether it can be built with the rustc release or if it requires features from beta/nightly. I don't know a specific example of one, but I also read that it is possible. I think that the cargo install should take care of installing such a library, but I don't think it's implemented yet. HTH!
