[INFO] fetching crate rundo 0.4.0...
[INFO] documenting rundo-0.4.0 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate rundo 0.4.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate rundo 0.4.0 on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rundo 0.4.0
[INFO] finished tweaking crates.io crate rundo 0.4.0
[INFO] tweaked toml for crates.io crate rundo 0.4.0 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rundo_attrs v0.4.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6ec10e5f6c81031dbc348c88890beeb3021ff34d988235c9e923244097dbf58c
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "6ec10e5f6c81031dbc348c88890beeb3021ff34d988235c9e923244097dbf58c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6ec10e5f6c81031dbc348c88890beeb3021ff34d988235c9e923244097dbf58c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6ec10e5f6c81031dbc348c88890beeb3021ff34d988235c9e923244097dbf58c", kill_on_drop: false }`
[INFO] [stdout] 6ec10e5f6c81031dbc348c88890beeb3021ff34d988235c9e923244097dbf58c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c9b1740e3508de7207fe77801e800077a209860bc5fca4776e4c48bccf004760
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "c9b1740e3508de7207fe77801e800077a209860bc5fca4776e4c48bccf004760", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde_json v1.0.57
[INFO] [stderr]    Compiling difference v2.0.0
[INFO] [stderr]    Compiling proc-macro2 v0.2.3
[INFO] [stderr]     Checking hostname v0.1.5
[INFO] [stderr]     Checking rundo_types v0.4.0
[INFO] [stderr]    Compiling quote v0.4.2
[INFO] [stderr]    Compiling syn v0.12.15
[INFO] [stderr]     Checking bson v0.11.1
[INFO] [stderr]    Compiling rundo_attrs v0.4.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/rundo_attrs-0.4.0/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(proc_macro)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rundo_attrs`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "c9b1740e3508de7207fe77801e800077a209860bc5fca4776e4c48bccf004760", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c9b1740e3508de7207fe77801e800077a209860bc5fca4776e4c48bccf004760", kill_on_drop: false }`
[INFO] [stdout] c9b1740e3508de7207fe77801e800077a209860bc5fca4776e4c48bccf004760