[INFO] cloning repository https://github.com/maelvalais/rust-chat
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/maelvalais/rust-chat" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmaelvalais%2Frust-chat", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmaelvalais%2Frust-chat'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ddd63a81b2bc7d15709d81e3dfc79bf30bdb9c9e
[INFO] documenting maelvalais/rust-chat 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%2Fmaelvalais%2Frust-chat" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/maelvalais/rust-chat 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/maelvalais/rust-chat
[INFO] finished tweaking git repo https://github.com/maelvalais/rust-chat
[INFO] tweaked toml for git repo https://github.com/maelvalais/rust-chat written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/maelvalais/rust-chat 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-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] 5b51952639af74f68b563cf96aac8dbf9aec0d8e34d575449ad6c4e0aaf1a0dc
[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" "5b51952639af74f68b563cf96aac8dbf9aec0d8e34d575449ad6c4e0aaf1a0dc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5b51952639af74f68b563cf96aac8dbf9aec0d8e34d575449ad6c4e0aaf1a0dc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b51952639af74f68b563cf96aac8dbf9aec0d8e34d575449ad6c4e0aaf1a0dc", kill_on_drop: false }`
[INFO] [stdout] 5b51952639af74f68b563cf96aac8dbf9aec0d8e34d575449ad6c4e0aaf1a0dc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] 785caf7cfda7dcc208d9f969ad97681df7278506b4d97763fb3eee1eedd69344
[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" "785caf7cfda7dcc208d9f969ad97681df7278506b4d97763fb3eee1eedd69344", 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]    Compiling cc v1.0.4
[INFO] [stderr]     Checking libc v0.2.37
[INFO] [stderr]     Checking rustc-demangle v0.1.7
[INFO] [stderr]     Checking log v0.4.1
[INFO] [stderr]     Checking atty v0.2.6
[INFO] [stderr]     Checking clap v2.30.0
[INFO] [stderr]    Compiling backtrace-sys v0.1.16
[INFO] [stderr]     Checking backtrace v0.3.5
[INFO] [stderr]     Checking error-chain v0.11.0
[INFO] [stderr]  Documenting rust-chat 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:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(vec_remove_item)]
[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 `rust-chat`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type bin --crate-name rust_chat 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 clap=/opt/rustwide/target/debug/deps/libclap-7f3b6c1461868c93.rmeta --extern colored=/opt/rustwide/target/debug/deps/libcolored-e876f10a7d0ded05.rmeta --extern error_chain=/opt/rustwide/target/debug/deps/liberror_chain-41419429a3614ed8.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-a2dfb7c9c6a5ce50.rmeta --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "785caf7cfda7dcc208d9f969ad97681df7278506b4d97763fb3eee1eedd69344", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "785caf7cfda7dcc208d9f969ad97681df7278506b4d97763fb3eee1eedd69344", kill_on_drop: false }`
[INFO] [stdout] 785caf7cfda7dcc208d9f969ad97681df7278506b4d97763fb3eee1eedd69344