[INFO] cloning repository https://github.com/j-browne/reaction_efficiency
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/j-browne/reaction_efficiency" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fj-browne%2Freaction_efficiency", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fj-browne%2Freaction_efficiency'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1872e71df6e1838342e20eca6dd98f410e138773
[INFO] documenting j-browne/reaction_efficiency 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%2Fj-browne%2Freaction_efficiency" "/workspace/builds/worker-25/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-25/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/j-browne/reaction_efficiency 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/j-browne/reaction_efficiency
[INFO] finished tweaking git repo https://github.com/j-browne/reaction_efficiency
[INFO] tweaked toml for git repo https://github.com/j-browne/reaction_efficiency written to /workspace/builds/worker-25/source/Cargo.toml
[INFO] crate git repo https://github.com/j-browne/reaction_efficiency 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded anyhow v1.0.32
[INFO] [stderr]   Downloaded serde_json v1.0.58
[INFO] [stderr]   Downloaded structopt-derive v0.4.11
[INFO] [stderr]   Downloaded structopt v0.3.18
[INFO] [stderr]   Downloaded syn v1.0.42
[INFO] [stderr]   Downloaded libc v0.2.78
[INFO] [stderr]   Downloaded serde_derive v1.0.116
[INFO] [stderr]   Downloaded hermit-abi v0.1.16
[INFO] [stderr]   Downloaded rayon-core v1.8.1
[INFO] [stderr]   Downloaded serde v1.0.116
[INFO] [stderr]   Downloaded ppv-lite86 v0.2.9
[INFO] [stderr]   Downloaded rayon v1.4.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-25/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-25/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] [stdout] ccbeba1a5ecc5738bca674d3863781bc1425a539e7f933dbeeb6f195680eb27e
[INFO] running `Command { std: "docker" "start" "-a" "ccbeba1a5ecc5738bca674d3863781bc1425a539e7f933dbeeb6f195680eb27e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ccbeba1a5ecc5738bca674d3863781bc1425a539e7f933dbeeb6f195680eb27e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ccbeba1a5ecc5738bca674d3863781bc1425a539e7f933dbeeb6f195680eb27e", kill_on_drop: false }`
[INFO] [stdout] ccbeba1a5ecc5738bca674d3863781bc1425a539e7f933dbeeb6f195680eb27e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-25/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-25/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] ffd0841c0e372c9b45ea07bfb9eb0dca40b277d1b9b644a25df438ee8c2f83c2
[INFO] running `Command { std: "docker" "start" "-a" "ffd0841c0e372c9b45ea07bfb9eb0dca40b277d1b9b644a25df438ee8c2f83c2", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.78
[INFO] [stderr]    Compiling syn v1.0.42
[INFO] [stderr]    Compiling rayon-core v1.8.1
[INFO] [stderr]    Compiling serde v1.0.116
[INFO] [stderr]    Compiling anyhow v1.0.32
[INFO] [stderr]     Checking ppv-lite86 v0.2.9
[INFO] [stderr]    Compiling serde_json v1.0.58
[INFO] [stderr]    Compiling serde_derive v1.0.116
[INFO] [stderr]    Compiling rayon v1.4.1
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking getrandom v0.1.15
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking crossbeam-channel v0.4.4
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]    Compiling structopt-derive v0.4.11
[INFO] [stderr]     Checking structopt v0.3.18
[INFO] [stderr]  Documenting reaction_efficiency 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(bool_to_option)]
[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 `reaction_efficiency`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name reaction_efficiency src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=4b3687583f044a14 -L dependency=/opt/rustwide/target/debug/deps --extern anyhow=/opt/rustwide/target/debug/deps/libanyhow-cac8b837a4a146f1.rmeta --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-1479f2b7adeaa2b6.rmeta --extern rand=/opt/rustwide/target/debug/deps/librand-bd1ffa3d12cc980f.rmeta --extern rayon=/opt/rustwide/target/debug/deps/librayon-39cb788e8eb96c3c.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-86ec4a90e465530c.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-8297c98dec6f6c03.so --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-e56e886159b5083f.rmeta --extern structopt=/opt/rustwide/target/debug/deps/libstructopt-280cdd608b5c0f43.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "ffd0841c0e372c9b45ea07bfb9eb0dca40b277d1b9b644a25df438ee8c2f83c2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ffd0841c0e372c9b45ea07bfb9eb0dca40b277d1b9b644a25df438ee8c2f83c2", kill_on_drop: false }`
[INFO] [stdout] ffd0841c0e372c9b45ea07bfb9eb0dca40b277d1b9b644a25df438ee8c2f83c2