Nightly `rustc-dev` can't be used in cross-compilation

Bug

I've made a minimal reproducible repo: https://github.com/tombh/nightly_cross_minimal_repro

Pasting main.rs:

#![feature(rustc_private)]

extern crate rustc_ast;
extern crate rustc_driver;
extern crate rustc_macros;

fn main() {
    println!("{}", rustc_ast::node_id::CRATE_NODE_ID)
}

The build commands are here: https://github.com/tombh/nightly_cross_minimal_repro/blob/main/.github/workflows/ci.yml

Pasting the most relevant part:

rustup toolchain install nightly-2024-09-30
rustup default nightly-2023-09-30
rustup target add aarch64-unknown-linux-gnu
rustup component add rust-src rustc-dev-aarch64-unknown-linux-gnu llvm-tools
...
cargo -v build --locked --release --target aarch64-unknown-linux-gnu

And here is the failing build: https://github.com/tombh/nightly_cross_minimal_repro/actions/runs/11463471346/job/31897390824#step:5:9

Also, just out of interest, here is a failing build with a more recent nightly (nightly-2024-10-21), it fails differently, it can't find derive_where: https://github.com/tombh/nightly_cross_minimal_repro/actions/runs/11463505291/job/31897508604#step:5:9

Relevant Issues

• The bug is being discussed in a rustup issue: https://github.com/rust-lang/rustup/issues/3255. That is where it was suggested that this is rather a rust or cargo issue.
• #62447
• #70838

Start by reproducing the commands in .github/workflows/ci.yml against the minimal main.rs repository for the two nightly toolchains. Compare both failure modes, then read rustup#3255, #62447, and #70838 to establish component ownership and the expected cross-compilation behavior; done means the root cause and an actionable fix location are confirmed.