Adding this for posterity in case someone else finds themselves here.
My particular use case was for nightly formatting like so: cargo +nightly fmt in a script that formats all files.
I was able to work around this by installing the nightly toolchain and changing the above to rustup run nightly cargo fmt, then adding the unstable_features = true option to the rustfmt.toml.
To quote @figsoda on the topic:
+<toolchain> is a rustup feature and fenix doesn’t currently support it. You should be able to just remove the +nightly argument and the same command should work. You can make a wrapper for cargo (and possibly other components) that skips the first argument if it starts with +. I’m not sure that this will ever be implemented within fenix, if it gets implemented it will probably be a separate tool that wraps nix and uses fenix under the hood.
Adding this for posterity in case someone else finds themselves here.
My particular use case was for nightly formatting like so:
cargo +nightly fmtin a script that formats all files.I was able to work around this by installing the nightly toolchain and changing the above to
rustup run nightly cargo fmt, then adding theunstable_features = trueoption to therustfmt.toml.To quote @figsoda on the topic: