[INFO] cloning repository https://github.com/kuy/dining-philosophers-aa
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kuy/dining-philosophers-aa" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuy%2Fdining-philosophers-aa", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkuy%2Fdining-philosophers-aa'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] cb14eba0fb81c51f959332de557d9dec41c18a3b
[INFO] documenting kuy/dining-philosophers-aa 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%2Fkuy%2Fdining-philosophers-aa" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kuy/dining-philosophers-aa 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/kuy/dining-philosophers-aa
[INFO] finished tweaking git repo https://github.com/kuy/dining-philosophers-aa
[INFO] tweaked toml for git repo https://github.com/kuy/dining-philosophers-aa written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/kuy/dining-philosophers-aa 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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-timer v0.3.0
[INFO] [stderr]   Downloaded async-std v0.99.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] ae0f8d88f61768a971e367a5b3afd76a90e2ca8902fcad975255b0dc84aa9827
[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" "ae0f8d88f61768a971e367a5b3afd76a90e2ca8902fcad975255b0dc84aa9827", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ae0f8d88f61768a971e367a5b3afd76a90e2ca8902fcad975255b0dc84aa9827", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ae0f8d88f61768a971e367a5b3afd76a90e2ca8902fcad975255b0dc84aa9827", kill_on_drop: false }`
[INFO] [stdout] ae0f8d88f61768a971e367a5b3afd76a90e2ca8902fcad975255b0dc84aa9827
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] a9b719f9637eb8804e158ca9ddf672981a5045c75b49bf4e07da1d353853faf2
[INFO] running `Command { std: "docker" "start" "-a" "a9b719f9637eb8804e158ca9ddf672981a5045c75b49bf4e07da1d353853faf2", kill_on_drop: false }`
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking crossbeam-channel v0.3.9
[INFO] [stderr]     Checking async-task v1.0.0
[INFO] [stderr]     Checking log v0.4.8
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking mio-uds v0.6.7
[INFO] [stderr]     Checking futures-executor-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures-timer v0.3.0
[INFO] [stderr]     Checking async-std v0.99.3
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/async-std-0.99.3/src/lib.rs:30:1
[INFO] [stdout]    |
[INFO] [stdout] 30 | #![feature(async_await)]
[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 compile `async-std`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "a9b719f9637eb8804e158ca9ddf672981a5045c75b49bf4e07da1d353853faf2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a9b719f9637eb8804e158ca9ddf672981a5045c75b49bf4e07da1d353853faf2", kill_on_drop: false }`
[INFO] [stdout] a9b719f9637eb8804e158ca9ddf672981a5045c75b49bf4e07da1d353853faf2