[INFO] cloning repository https://github.com/acdenisSK/kitty-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/acdenisSK/kitty-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FacdenisSK%2Fkitty-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FacdenisSK%2Fkitty-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7d0e4c52ac4d3ea71c117b9bfcc4bc7536920269
[INFO] documenting acdenisSK/kitty-rs against 1.46.0 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FacdenisSK%2Fkitty-rs" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/acdenisSK/kitty-rs on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/acdenisSK/kitty-rs
[INFO] finished tweaking git repo https://github.com/acdenisSK/kitty-rs
[INFO] tweaked toml for git repo https://github.com/acdenisSK/kitty-rs written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/acdenisSK/kitty-rs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0b9f13366cf35f5464bd4c20af30b932e0a857036eb0451dd78eb8a686dbbc5f
[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" "0b9f13366cf35f5464bd4c20af30b932e0a857036eb0451dd78eb8a686dbbc5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0b9f13366cf35f5464bd4c20af30b932e0a857036eb0451dd78eb8a686dbbc5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0b9f13366cf35f5464bd4c20af30b932e0a857036eb0451dd78eb8a686dbbc5f", kill_on_drop: false }`
[INFO] [stdout] 0b9f13366cf35f5464bd4c20af30b932e0a857036eb0451dd78eb8a686dbbc5f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8623222fc671847de3eb74ff21a096168de6c211c73207005cfb0ea9248bf886
[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" "8623222fc671847de3eb74ff21a096168de6c211c73207005cfb0ea9248bf886", kill_on_drop: false }`
[INFO] [stderr]    Compiling serenity v0.9.0-rc.0
[INFO] [stderr]     Checking typemap_rev v0.1.3
[INFO] [stderr]    Compiling tokio-macros v0.2.5
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking rustls v0.18.0
[INFO] [stderr]     Checking webpki-roots v0.17.0
[INFO] [stderr]     Checking webpki-roots v0.19.0
[INFO] [stderr]    Compiling command_attr v0.3.0-rc.0
[INFO] [stderr]    Compiling async-trait v0.1.36
[INFO] [stderr]     Checking rustls v0.16.0
[INFO] [stderr]     Checking tungstenite v0.10.1
[INFO] [stderr]     Checking pretty_env_logger v0.4.0
[INFO] [stderr]     Checking serde_urlencoded v0.6.1
[INFO] [stderr]     Checking serde_json v1.0.57
[INFO] [stderr]     Checking chrono v0.4.13
[INFO] [stderr]     Checking futures-util v0.3.5
[INFO] [stderr]     Checking tokio v0.2.22
[INFO] [stderr]     Checking futures-executor v0.3.5
[INFO] [stderr]     Checking futures v0.3.5
[INFO] [stderr]     Checking async-tls v0.6.0
[INFO] [stderr]     Checking tokio-util v0.3.1
[INFO] [stderr]     Checking tokio-rustls v0.14.0
[INFO] [stderr]     Checking async-tungstenite v0.4.2
[INFO] [stderr]     Checking h2 v0.2.6
[INFO] [stderr]     Checking hyper v0.13.7
[INFO] [stderr]     Checking hyper-rustls v0.21.0
[INFO] [stderr]     Checking reqwest v0.10.7
[INFO] [stderr]  Documenting kitty-rs 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:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(stmt_expr_attributes)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(proc_macro_hygiene)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(async_closure)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 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 `kitty-rs`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name kitty_rs 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 chrono=/opt/rustwide/target/debug/deps/libchrono-ce0dd74fdbd4c275.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-958bf2a074a4960f.rmeta --extern pretty_env_logger=/opt/rustwide/target/debug/deps/libpretty_env_logger-eb5ecfc126f3daab.rmeta --extern rand=/opt/rustwide/target/debug/deps/librand-fd953417ae6485af.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-5cfea2d08f51745e.rmeta --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-c48fd45b36f14c28.rmeta --extern serenity=/opt/rustwide/target/debug/deps/libserenity-4359b069e98a599a.rmeta --extern tokio=/opt/rustwide/target/debug/deps/libtokio-00a58facadc7bd0d.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "8623222fc671847de3eb74ff21a096168de6c211c73207005cfb0ea9248bf886", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8623222fc671847de3eb74ff21a096168de6c211c73207005cfb0ea9248bf886", kill_on_drop: false }`
[INFO] [stdout] 8623222fc671847de3eb74ff21a096168de6c211c73207005cfb0ea9248bf886