[INFO] cloning repository https://github.com/wasm-data-structures/red-black-tree
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/wasm-data-structures/red-black-tree" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwasm-data-structures%2Fred-black-tree", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwasm-data-structures%2Fred-black-tree'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ed83cf69671e10961ccb1024a54db16cc946b42d
[INFO] testing wasm-data-structures/red-black-tree against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwasm-data-structures%2Fred-black-tree" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/wasm-data-structures/red-black-tree on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/wasm-data-structures/red-black-tree
[INFO] finished tweaking git repo https://github.com/wasm-data-structures/red-black-tree
[INFO] tweaked toml for git repo https://github.com/wasm-data-structures/red-black-tree written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/wasm-data-structures/red-black-tree already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] fbbeb0795f5eaaa58a6eee0795e166b25d1d1fe6d3d65aff8c6e1ea57af18791
[INFO] running `Command { std: "docker" "start" "-a" "fbbeb0795f5eaaa58a6eee0795e166b25d1d1fe6d3d65aff8c6e1ea57af18791", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fbbeb0795f5eaaa58a6eee0795e166b25d1d1fe6d3d65aff8c6e1ea57af18791", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fbbeb0795f5eaaa58a6eee0795e166b25d1d1fe6d3d65aff8c6e1ea57af18791", kill_on_drop: false }`
[INFO] [stdout] fbbeb0795f5eaaa58a6eee0795e166b25d1d1fe6d3d65aff8c6e1ea57af18791
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f5d8479f59302c514261694c6ea650b9d6d57d653ac089ca4239d3c30b5f6ee2
[INFO] running `Command { std: "docker" "start" "-a" "f5d8479f59302c514261694c6ea650b9d6d57d653ac089ca4239d3c30b5f6ee2", kill_on_drop: false }`
[INFO] [stderr]    Compiling red-black-tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(lang_items, start)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0522]: definition of an unknown language item: `panic_fmt`
[INFO] [stdout]  --> src/main.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #[lang = "panic_fmt"] fn panic_fmt() -> ! { loop {} }
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: `#[panic_handler]` function required, but not found
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0522, E0554.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0522`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `red-black-tree` due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "f5d8479f59302c514261694c6ea650b9d6d57d653ac089ca4239d3c30b5f6ee2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f5d8479f59302c514261694c6ea650b9d6d57d653ac089ca4239d3c30b5f6ee2", kill_on_drop: false }`
[INFO] [stdout] f5d8479f59302c514261694c6ea650b9d6d57d653ac089ca4239d3c30b5f6ee2