Cargo cannot build `compiler_builtins` for `aarch64-unknown-linux-musl` about xargo

[RalfJung]

I probably can't help much with your actual problem, but...

A challenge here is that the temporary Cargo.toml gets cleaned up xargo.

you can set XARGO_KEEP_TEMP to disable the cleanup.

It sounds like there might be a compiler_builtins but the crate does not exist for this architecture, or cannot be found in the sysroot source?

[littlebenlittle]

Looks like compiler_builtins is installed by default.

It seems strange that cargo is complaining that the version isn't specified.

It sounds like there might be a compiler_builtins but the crate does not exist for this architecture, or cannot be found in the sysroot source?

How can I check what's in the sysroot for my build?

[Am3ra]

hmm, getting the same issue with a new project, almost empty, and have no Idea why.

For reference, these are the steps I'm taking to reproduce:

https://wiki.osdev.org/Raspberry_Pi_Bare_Bones_Rust

[RalfJung]

The same error also appears in #321 during CI, so there's definitely some rustc/cargo change that happened here. But I won't have time to look into this for now... help would be much appreciated!

[a-nickol]

Is it because of the missing source for compiler_builtins in rust-src? I am not sure if it had been there before.

ln ~/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library there is no compiler_builtins folder.

By adding git = "https://github.com/rust-lang/compiler-builtins" to the Cargo.toml of the problematic build, the problem is fixed.

[a-nickol]

I created a patch that adds the git reference, but I'm not sure what the previous behavior was.