cross-rs/cross · error

toolchain ` ` may not run on image

Error message

toolchain `{toolchain}` may not run on image `{image}`

What it means

Warning in run after setup: the selected image's platform architecture differs from the host architecture of the chosen toolchain (e.g. an aarch64 Docker image with an x86_64 toolchain), so the toolchain binaries may not execute inside the container even though the target itself is supported. Cross proceeds but warns that the combination is likely broken.

Solutions

1. Pick a toolchain whose host architecture matches the image platform architecture
2. Choose or build a cross image whose platform matches the toolchain host
3. Use a toolchain installed inside the image rather than mounting a host-architecture toolchain

When it happens

Trigger: Thrown at src/lib.rs:553 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of cross-rs/cross@8c1a8aa4b6 (2026-09-13). Data as JSON: /api/errors/e62118ad161aa4a5. Report an issue: GitHub.

Appendix: source

Thrown at src/lib.rs:553

            toolchain,
            is_remote,
            engine,
            image,
        } = match setup(&host_version_meta, &metadata, &args, target_list, msg_info)? {
            Some(setup) => setup,
            _ => {
                return Ok(None);
            }
        };

        config.confusable_target(&target, msg_info)?;

        let picked_generic_channel =
            matches!(toolchain.channel.as_str(), "stable" | "beta" | "nightly");

        if image.platform.target.is_supported(Some(&target)) {
            if image.platform.architecture != toolchain.host().architecture {
                msg_info.warn(format_args!(
                    "toolchain `{toolchain}` may not run on image `{image}`"
                ))?;
            }
            let mut is_nightly = toolchain.channel.contains("nightly");
            let mut rustc_version = None;
            if let Some((version, channel, commit)) = toolchain.rustc_version()? {
                if picked_generic_channel && toolchain.date.is_none() {
                    warn_host_version_mismatch(
                        &host_version_meta,
                        &toolchain,
                        &version,
                        &commit,
                        msg_info,
                    )?;
                }
                is_nightly = channel == Channel::Nightly;
                rustc_version = Some(version);
            }

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