[INFO] cloning repository https://github.com/ajmwagar/tread
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ajmwagar/tread" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fajmwagar%2Ftread", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fajmwagar%2Ftread'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 76b68441bf91b201c2d61bace6f45ac6159f44ae
[INFO] documenting ajmwagar/tread 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%2Fajmwagar%2Ftread" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ajmwagar/tread 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/ajmwagar/tread
[INFO] finished tweaking git repo https://github.com/ajmwagar/tread
[INFO] tweaked toml for git repo https://github.com/ajmwagar/tread written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/ajmwagar/tread 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] c3f47f68cf733b3b19d74aec754f98384a6d7fb4ccda20d1ed7889c2f51de24e
[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" "c3f47f68cf733b3b19d74aec754f98384a6d7fb4ccda20d1ed7889c2f51de24e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c3f47f68cf733b3b19d74aec754f98384a6d7fb4ccda20d1ed7889c2f51de24e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c3f47f68cf733b3b19d74aec754f98384a6d7fb4ccda20d1ed7889c2f51de24e", kill_on_drop: false }`
[INFO] [stdout] c3f47f68cf733b3b19d74aec754f98384a6d7fb4ccda20d1ed7889c2f51de24e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 731689695a038f1e7ca6e413e2dbec26e4b4712f3aab22f499319195132aa826
[INFO] running `Command { std: "docker" "start" "-a" "731689695a038f1e7ca6e413e2dbec26e4b4712f3aab22f499319195132aa826", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.29
[INFO] [stderr]    Compiling unicode-segmentation v1.2.1
[INFO] [stderr]     Checking termion v1.5.2
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling structopt-derive v0.2.15
[INFO] [stderr]     Checking structopt v0.2.15
[INFO] [stderr]  Documenting tread v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error: Could not document `tread`.
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(duration_float)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] Caused by:
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name tread src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern structopt=/opt/rustwide/target/debug/deps/libstructopt-b6d548561083383d.rmeta --extern termion=/opt/rustwide/target/debug/deps/libtermion-89228d42ef37ebae.rmeta --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "731689695a038f1e7ca6e413e2dbec26e4b4712f3aab22f499319195132aa826", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "731689695a038f1e7ca6e413e2dbec26e4b4712f3aab22f499319195132aa826", kill_on_drop: false }`
[INFO] [stdout] 731689695a038f1e7ca6e413e2dbec26e4b4712f3aab22f499319195132aa826