[INFO] cloning repository https://github.com/liufuyang/rust-word-count
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/liufuyang/rust-word-count" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliufuyang%2Frust-word-count", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliufuyang%2Frust-word-count'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 12f7058dca5697d286630de9cff648d752f40abc
[INFO] documenting liufuyang/rust-word-count against 1.61.0 for beta-1.62-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fliufuyang%2Frust-word-count" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/liufuyang/rust-word-count on toolchain 1.61.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/liufuyang/rust-word-count
[INFO] finished tweaking git repo https://github.com/liufuyang/rust-word-count
[INFO] tweaked toml for git repo https://github.com/liufuyang/rust-word-count written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/liufuyang/rust-word-count already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rayon-core v1.5.0
[INFO] [stderr]   Downloaded rayon v1.1.0
[INFO] [stderr]   Downloaded crossbeam v0.7.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] e91bb6d0c0fc7910fdf4503d2cbec6abbefa797a97f4148a7add5a1d461a3ecc
[INFO] running `Command { std: "docker" "start" "-a" "e91bb6d0c0fc7910fdf4503d2cbec6abbefa797a97f4148a7add5a1d461a3ecc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e91bb6d0c0fc7910fdf4503d2cbec6abbefa797a97f4148a7add5a1d461a3ecc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e91bb6d0c0fc7910fdf4503d2cbec6abbefa797a97f4148a7add5a1d461a3ecc", kill_on_drop: false }`
[INFO] [stdout] e91bb6d0c0fc7910fdf4503d2cbec6abbefa797a97f4148a7add5a1d461a3ecc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a3f9f40fc29991c10d00a5198a037510e277c47db4b23b585de53bdb773aca8d
[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" "a3f9f40fc29991c10d00a5198a037510e277c47db4b23b585de53bdb773aca8d", kill_on_drop: false }`
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling rayon-core v1.5.0
[INFO] [stderr]     Checking num_cpus v1.10.1
[INFO] [stderr]     Checking crossbeam-utils v0.6.5
[INFO] [stderr]     Checking crossbeam-epoch v0.7.1
[INFO] [stderr]     Checking crossbeam-queue v0.1.2
[INFO] [stderr]     Checking crossbeam-channel v0.3.8
[INFO] [stderr]     Checking crossbeam-deque v0.6.3
[INFO] [stderr]     Checking crossbeam-deque v0.7.1
[INFO] [stderr]     Checking crossbeam v0.7.1
[INFO] [stderr]     Checking rayon v1.1.0
[INFO] [stderr]  Documenting rust_word_count 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:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(duration_float)]
[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 document `rust_word_count`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name rust_word_count src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=9f482ba2482c36e5 -L dependency=/opt/rustwide/target/debug/deps --extern crossbeam=/opt/rustwide/target/debug/deps/libcrossbeam-52c9c3e7159ea6bf.rmeta --extern rayon=/opt/rustwide/target/debug/deps/librayon-d7db84b026697151.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "a3f9f40fc29991c10d00a5198a037510e277c47db4b23b585de53bdb773aca8d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a3f9f40fc29991c10d00a5198a037510e277c47db4b23b585de53bdb773aca8d", kill_on_drop: false }`
[INFO] [stdout] a3f9f40fc29991c10d00a5198a037510e277c47db4b23b585de53bdb773aca8d