[INFO] cloning repository https://github.com/justinwoo/tokio-process-test
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/justinwoo/tokio-process-test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjustinwoo%2Ftokio-process-test", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjustinwoo%2Ftokio-process-test'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5a42b3265e927c5cf86aa806d6382e15bb78e843
[INFO] documenting justinwoo/tokio-process-test 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%2Fjustinwoo%2Ftokio-process-test" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/justinwoo/tokio-process-test 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/justinwoo/tokio-process-test
[INFO] finished tweaking git repo https://github.com/justinwoo/tokio-process-test
[INFO] tweaked toml for git repo https://github.com/justinwoo/tokio-process-test written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/justinwoo/tokio-process-test 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] 8407e2df0303f4c14a5db753dcb9d8243be8a03ec824b8bae1c1b17f125ead9a
[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" "8407e2df0303f4c14a5db753dcb9d8243be8a03ec824b8bae1c1b17f125ead9a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8407e2df0303f4c14a5db753dcb9d8243be8a03ec824b8bae1c1b17f125ead9a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8407e2df0303f4c14a5db753dcb9d8243be8a03ec824b8bae1c1b17f125ead9a", kill_on_drop: false }`
[INFO] [stdout] 8407e2df0303f4c14a5db753dcb9d8243be8a03ec824b8bae1c1b17f125ead9a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] a0285061c6198b422acc1f672631ad9006f5b58932cb77659f8d3b71ff85b2f9
[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" "a0285061c6198b422acc1f672631ad9006f5b58932cb77659f8d3b71ff85b2f9", kill_on_drop: false }`
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking tokio-executor v0.2.0-alpha.2
[INFO] [stderr]     Checking pin-project-lite v0.1.2
[INFO] [stderr]    Compiling memchr v2.3.0
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]     Checking mio v0.6.21
[INFO] [stderr]     Checking parking_lot v0.9.0
[INFO] [stderr]     Checking tokio v0.2.9
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking tokio-io v0.2.0-alpha.2
[INFO] [stderr]     Checking mio-uds v0.6.7
[INFO] [stderr]     Checking tokio-codec v0.2.0-alpha.2
[INFO] [stderr]     Checking tokio-sync v0.2.0-alpha.2
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/tokio-sync-0.2.0-alpha.2/src/lib.rs:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![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 `tokio-sync`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "a0285061c6198b422acc1f672631ad9006f5b58932cb77659f8d3b71ff85b2f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a0285061c6198b422acc1f672631ad9006f5b58932cb77659f8d3b71ff85b2f9", kill_on_drop: false }`
[INFO] [stdout] a0285061c6198b422acc1f672631ad9006f5b58932cb77659f8d3b71ff85b2f9