[INFO] fetching crate rustsynth 0.6.0...
[INFO] testing rustsynth-0.6.0 against beta-2025-09-21 for beta-1.91-3
[INFO] extracting crate rustsynth 0.6.0 into /workspace/builds/worker-0-tc2/source
[INFO] started tweaking crates.io crate rustsynth 0.6.0
[INFO] finished tweaking crates.io crate rustsynth 0.6.0
[INFO] tweaked toml for crates.io crate rustsynth 0.6.0 written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate rustsynth 0.6.0 on toolchain beta-2025-09-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate rustsynth 0.6.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1d185fb135bfaf1a56dd17462d0e636da194b3d9375165d23283cf349b11004b
[INFO] running `Command { std: "docker" "start" "-a" "1d185fb135bfaf1a56dd17462d0e636da194b3d9375165d23283cf349b11004b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1d185fb135bfaf1a56dd17462d0e636da194b3d9375165d23283cf349b11004b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1d185fb135bfaf1a56dd17462d0e636da194b3d9375165d23283cf349b11004b", kill_on_drop: false }`
[INFO] [stdout] 1d185fb135bfaf1a56dd17462d0e636da194b3d9375165d23283cf349b11004b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ff27e2f589e946d27976d9ab17aaa9e825655e4b3620d4d772d68665e8d05a52
[INFO] running `Command { std: "docker" "start" "-a" "ff27e2f589e946d27976d9ab17aaa9e825655e4b3620d4d772d68665e8d05a52", kill_on_drop: false }`
[INFO] [stderr]    Compiling glob v0.3.3
[INFO] [stderr]    Compiling prettyplease v0.2.37
[INFO] [stderr]    Compiling libc v0.2.175
[INFO] [stderr]    Compiling regex-syntax v0.8.6
[INFO] [stderr]    Compiling minimal-lexical v0.2.1
[INFO] [stderr]    Compiling either v1.15.0
[INFO] [stderr]    Compiling quote v1.0.40
[INFO] [stderr]    Compiling libloading v0.8.9
[INFO] [stderr]    Compiling nom v7.1.3
[INFO] [stderr]    Compiling bindgen v0.72.1
[INFO] [stderr]    Compiling bitflags v2.9.4
[INFO] [stderr]    Compiling itertools v0.13.0
[INFO] [stderr]    Compiling rustc-hash v2.1.1
[INFO] [stderr]    Compiling syn v2.0.106
[INFO] [stderr]    Compiling clang-sys v1.8.1
[INFO] [stderr]    Compiling regex-automata v0.4.10
[INFO] [stderr]    Compiling cexpr v0.6.0
[INFO] [stderr]    Compiling regex v1.11.2
[INFO] [stderr]    Compiling futures-macro v0.3.31
[INFO] [stderr]    Compiling thiserror-impl v2.0.16
[INFO] [stderr]    Compiling futures-util v0.3.31
[INFO] [stderr]    Compiling thiserror v2.0.16
[INFO] [stderr]    Compiling futures-executor v0.3.31
[INFO] [stderr]    Compiling futures v0.3.31
[INFO] [stderr]    Compiling rustsynth-sys v0.5.5
[INFO] [stderr]    Compiling rustsynth v0.6.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(doc_cfg)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rustsynth` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "ff27e2f589e946d27976d9ab17aaa9e825655e4b3620d4d772d68665e8d05a52", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ff27e2f589e946d27976d9ab17aaa9e825655e4b3620d4d772d68665e8d05a52", kill_on_drop: false }`
[INFO] [stdout] ff27e2f589e946d27976d9ab17aaa9e825655e4b3620d4d772d68665e8d05a52