[INFO] fetching crate mussh 3.1.2...
[INFO] documenting mussh-3.1.2 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate mussh 3.1.2 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate mussh 3.1.2 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 crates.io crate mussh 3.1.2
[INFO] finished tweaking crates.io crate mussh 3.1.2
[INFO] tweaked toml for crates.io crate mussh 3.1.2 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate mussh 3.1.2 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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 5db56453192be65cdbe23bf63275f7b60fdcb12c04984ff8604befe6c8721850
[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" "5db56453192be65cdbe23bf63275f7b60fdcb12c04984ff8604befe6c8721850", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5db56453192be65cdbe23bf63275f7b60fdcb12c04984ff8604befe6c8721850", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5db56453192be65cdbe23bf63275f7b60fdcb12c04984ff8604befe6c8721850", kill_on_drop: false }`
[INFO] [stdout] 5db56453192be65cdbe23bf63275f7b60fdcb12c04984ff8604befe6c8721850
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 399d5ddc1da53120892e63e28e6a16ff2db33268345e3f01d471ec6994dc0b1d
[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" "399d5ddc1da53120892e63e28e6a16ff2db33268345e3f01d471ec6994dc0b1d", 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 libc v0.2.68
[INFO] [stderr]    Compiling proc-macro2 v1.0.10
[INFO] [stderr]    Compiling syn v1.0.17
[INFO] [stderr]    Compiling slog v2.5.2
[INFO] [stderr]     Checking lazy_static v1.2.0
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]     Checking linked-hash-map v0.5.2
[INFO] [stderr]     Checking take_mut v0.2.2
[INFO] [stderr]     Checking wait_group v0.1.4
[INFO] [stderr]    Compiling openssl-sys v0.9.54
[INFO] [stderr]    Compiling libz-sys v1.0.25
[INFO] [stderr]    Compiling libssh2-sys v0.2.16
[INFO] [stderr]    Compiling libsqlite3-sys v0.17.2
[INFO] [stderr]    Compiling proc-macro-error-attr v0.4.12
[INFO] [stderr]    Compiling proc-macro-error v0.4.12
[INFO] [stderr]     Checking thread_local v1.0.1
[INFO] [stderr]     Checking crossbeam-utils v0.7.2
[INFO] [stderr]     Checking lru-cache v0.1.2
[INFO] [stderr]     Checking crossbeam-channel v0.4.2
[INFO] [stderr]     Checking slog-try v0.2.0
[INFO] [stderr]    Compiling quote v1.0.3
[INFO] [stderr]     Checking time v0.1.42
[INFO] [stderr]     Checking dirs-sys v0.3.4
[INFO] [stderr]     Checking parking_lot_core v0.7.0
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking dirs v1.0.5
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking dirs v2.0.2
[INFO] [stderr]     Checking slog-async v2.5.0
[INFO] [stderr]     Checking term v0.6.1
[INFO] [stderr]     Checking parking_lot v0.10.0
[INFO] [stderr]     Checking chrono v0.4.11
[INFO] [stderr]     Checking rusqlite v0.21.0
[INFO] [stderr]     Checking slog-term v2.5.0
[INFO] [stderr]    Compiling syn-mid v0.5.0
[INFO] [stderr]     Checking ssh2 v0.8.0
[INFO] [stderr]    Compiling serde_derive v1.0.106
[INFO] [stderr]     Checking toml v0.5.6
[INFO] [stderr]    Compiling getset v0.1.0
[INFO] [stderr]     Checking libmussh v1.1.3
[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/libmussh-1.1.3/src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(crate_visibility_modifier, error_iter)]
[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 `libmussh`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "399d5ddc1da53120892e63e28e6a16ff2db33268345e3f01d471ec6994dc0b1d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "399d5ddc1da53120892e63e28e6a16ff2db33268345e3f01d471ec6994dc0b1d", kill_on_drop: false }`
[INFO] [stdout] 399d5ddc1da53120892e63e28e6a16ff2db33268345e3f01d471ec6994dc0b1d