[INFO] cloning repository https://github.com/nakakura/tokio_udp_sendrecv_example
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nakakura/tokio_udp_sendrecv_example" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnakakura%2Ftokio_udp_sendrecv_example", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnakakura%2Ftokio_udp_sendrecv_example'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8a2d2acc59bb69de09d4bbf7552f535d131c016c
[INFO] documenting nakakura/tokio_udp_sendrecv_example 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%2Fnakakura%2Ftokio_udp_sendrecv_example" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nakakura/tokio_udp_sendrecv_example 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/nakakura/tokio_udp_sendrecv_example
[INFO] finished tweaking git repo https://github.com/nakakura/tokio_udp_sendrecv_example
[INFO] tweaked toml for git repo https://github.com/nakakura/tokio_udp_sendrecv_example written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/nakakura/tokio_udp_sendrecv_example 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 4faf27ada6ccb04cdffddd090e4bd7215b28a06690eddfc794ef763f205ea9fc
[INFO] running `Command { std: "docker" "start" "-a" "4faf27ada6ccb04cdffddd090e4bd7215b28a06690eddfc794ef763f205ea9fc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4faf27ada6ccb04cdffddd090e4bd7215b28a06690eddfc794ef763f205ea9fc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4faf27ada6ccb04cdffddd090e4bd7215b28a06690eddfc794ef763f205ea9fc", kill_on_drop: false }`
[INFO] [stdout] 4faf27ada6ccb04cdffddd090e4bd7215b28a06690eddfc794ef763f205ea9fc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] b66a39fedde1a2efb153163683a30528b6658a29966186d888f6042c7785aab5
[INFO] running `Command { std: "docker" "start" "-a" "b66a39fedde1a2efb153163683a30528b6658a29966186d888f6042c7785aab5", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.40
[INFO] [stderr]     Checking log v0.4.1
[INFO] [stderr]     Checking crossbeam-epoch v0.4.1
[INFO] [stderr]     Checking tokio-timer v0.2.3
[INFO] [stderr]     Checking crossbeam-deque v0.3.1
[INFO] [stderr]     Checking iovec v0.1.2
[INFO] [stderr]     Checking net2 v0.2.32
[INFO] [stderr]     Checking rand v0.4.2
[INFO] [stderr]     Checking num_cpus v1.8.0
[INFO] [stderr]     Checking bytes v0.4.7
[INFO] [stderr]     Checking mio v0.6.14
[INFO] [stderr]     Checking tokio-io v0.1.6
[INFO] [stderr]     Checking tokio-threadpool v0.1.3
[INFO] [stderr]     Checking tokio-reactor v0.1.1
[INFO] [stderr]     Checking tokio-fs v0.1.0
[INFO] [stderr]     Checking tokio-udp v0.1.0
[INFO] [stderr]     Checking tokio-tcp v0.1.0
[INFO] [stderr]     Checking tokio v0.1.6
[INFO] [stderr]  Documenting udp_sendrecv_tokio 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(drain_filter)]
[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 `udp_sendrecv_tokio`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type bin --crate-name udp_sendrecv_tokio src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=6989fed62e0c3a62 -L dependency=/opt/rustwide/target/debug/deps --extern bytes=/opt/rustwide/target/debug/deps/libbytes-58638d5b91a56f21.rmeta --extern futures=/opt/rustwide/target/debug/deps/libfutures-eca66cf27e465c6b.rmeta --extern tokio=/opt/rustwide/target/debug/deps/libtokio-fd67738afe85fe53.rmeta --extern tokio_io=/opt/rustwide/target/debug/deps/libtokio_io-ee6433e1ddc718b9.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "b66a39fedde1a2efb153163683a30528b6658a29966186d888f6042c7785aab5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b66a39fedde1a2efb153163683a30528b6658a29966186d888f6042c7785aab5", kill_on_drop: false }`
[INFO] [stdout] b66a39fedde1a2efb153163683a30528b6658a29966186d888f6042c7785aab5