Instructing Corrosion to use nightly when compiling my crate.

[IoIxD]

I'm trying to compile a crate that Rust doesn't support - Classic Mac OS - and use it with a C/C++ codebase I already have. This is possible thanks to steps outlined in this guide. Because this is using a fork of gcc, I don't expect much more effort in this working beyond what is described in that guide; the important part is having my crate build within the cmake script.

The roadblock I'm having is actually that I can't compile the crate due to it wanting a nightly feature.

-- Build files have been written to: /home/gavin/Projects/PowerBoot/build-PowerPC
[  0%] Built target cargo-prebuild_PowerNet
[  3%] Built target everest
[  5%] Built target p256m
warning: `/home/gavin/Projects/PowerBoot/PowerNet/.cargo/config` is deprecated in favor of `config.toml`
note: if you need to support cargo 1.38 or earlier, you can symlink `config` to `config.toml`
[ 22%] Built target libssh2_static
   Compiling PowerNet v0.1.0 (/home/gavin/Projects/PowerBoot/PowerNet)
error[E0554]: `#![feature]` may not be used on the stable release channel
 --> src/lib.rs:5:1
  |
5 | #![feature(lang_items)]

lang_items is needed in order to implement a panic_handler/eh_personality as I do not have the std crate avaliable to me.

All I can find on doing this is something internal to corrosion titled "Rust_IS_NIGHTLY"; I didn't expect setting it to work, and indeed it does not.

set(Rust_IS_NIGHTLY 1 CACHE INTERNAL "" FORCE)
corrosion_import_crate(
  MANIFEST_PATH PowerNet/Cargo.toml
  NO_DEFAULT_FEATURES
  NO_STD
  NO_LINKER_OVERRIDE
  NO_USES_TERMINAL
)

What do I do?

[IoIxD]

It ended up not being what I needed, this entire thing is not possible with Corrosion and I had to do things myself, but I'm interested in the answer.

[jschwe]

Rust_TOOLCHAIN allows you to select a different rust toolchain, e.g. nightly.