[INFO] cloning repository https://github.com/japrogramer/RustLand
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/japrogramer/RustLand" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjaprogramer%2FRustLand", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjaprogramer%2FRustLand'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 41ba75dd28ddc348cbea3f399dc2b27d70505057
[INFO] documenting japrogramer/RustLand against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjaprogramer%2FRustLand" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/japrogramer/RustLand 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 git repo https://github.com/japrogramer/RustLand
[INFO] finished tweaking git repo https://github.com/japrogramer/RustLand
[INFO] tweaked toml for git repo https://github.com/japrogramer/RustLand written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/japrogramer/RustLand already has a lockfile, it will not be regenerated
[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]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] 1c53448a8e4183ba1ebd29a30157c874ce1f2a132791c62f6fd19d1a01e44471
[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" "1c53448a8e4183ba1ebd29a30157c874ce1f2a132791c62f6fd19d1a01e44471", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1c53448a8e4183ba1ebd29a30157c874ce1f2a132791c62f6fd19d1a01e44471", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1c53448a8e4183ba1ebd29a30157c874ce1f2a132791c62f6fd19d1a01e44471", kill_on_drop: false }`
[INFO] [stdout] 1c53448a8e4183ba1ebd29a30157c874ce1f2a132791c62f6fd19d1a01e44471
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] 1ae8d9f4368cd541370c9db30ec24d85d57262e613364c54e24a26268809759a
[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" "1ae8d9f4368cd541370c9db30ec24d85d57262e613364c54e24a26268809759a", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]     Checking futures-sink v0.3.1
[INFO] [stderr]     Checking futures-core v0.3.1
[INFO] [stderr]    Compiling serde v1.0.101
[INFO] [stderr]    Compiling cpython v0.3.0
[INFO] [stderr]    Compiling num-traits v0.2.9
[INFO] [stderr]    Compiling python3-sys v0.3.0
[INFO] [stderr]     Checking futures-channel v0.3.1
[INFO] [stderr]    Compiling proc-macro-hack v0.5.11
[INFO] [stderr]    Compiling serde_derive v1.0.101
[INFO] [stderr]    Compiling futures-macro v0.3.1
[INFO] [stderr]     Checking futures-util v0.3.1
[INFO] [stderr]     Checking futures-executor v0.3.1
[INFO] [stderr]     Checking futures v0.3.1
[INFO] [stderr]  Documenting course v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(label_break_value)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: Could not document `course`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name rl_course src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern cpython=/opt/rustwide/target/debug/deps/libcpython-cff2e5fa6fa297e1.rmeta --extern futures=/opt/rustwide/target/debug/deps/libfutures-22a1aaf1e4a99aca.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-a8c5ac997155d6eb.rmeta --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "1ae8d9f4368cd541370c9db30ec24d85d57262e613364c54e24a26268809759a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1ae8d9f4368cd541370c9db30ec24d85d57262e613364c54e24a26268809759a", kill_on_drop: false }`
[INFO] [stdout] 1ae8d9f4368cd541370c9db30ec24d85d57262e613364c54e24a26268809759a