[INFO] fetching crate mech-program 0.0.5...
[INFO] documenting mech-program-0.0.5 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate mech-program 0.0.5 into /workspace/builds/worker-38/source
[INFO] validating manifest of crates.io crate mech-program 0.0.5 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mech-program 0.0.5
[INFO] finished tweaking crates.io crate mech-program 0.0.5
[INFO] tweaked toml for crates.io crate mech-program 0.0.5 written to /workspace/builds/worker-38/source/Cargo.toml
[INFO] crate crates.io crate mech-program 0.0.5 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", 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]  Downloading crates ...
[INFO] [stderr]   Downloaded ws v0.9.1
[INFO] [stderr]   Downloaded serde_json v1.0.52
[INFO] [stderr]   Downloaded backtrace v0.3.41
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-38/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-38/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 586dc3405a46a87506aea4f527c55bc936d590af5b839763c59d56e6fdd21de2
[INFO] running `Command { std: "docker" "start" "-a" "586dc3405a46a87506aea4f527c55bc936d590af5b839763c59d56e6fdd21de2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "586dc3405a46a87506aea4f527c55bc936d590af5b839763c59d56e6fdd21de2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "586dc3405a46a87506aea4f527c55bc936d590af5b839763c59d56e6fdd21de2", kill_on_drop: false }`
[INFO] [stdout] 586dc3405a46a87506aea4f527c55bc936d590af5b839763c59d56e6fdd21de2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-38/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-38/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7aa585fba0dbe5010acb22a7e119acce55cfaf338d3166611603db9131ef3bbe
[INFO] running `Command { std: "docker" "start" "-a" "7aa585fba0dbe5010acb22a7e119acce55cfaf338d3166611603db9131ef3bbe", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]     Checking futures v0.1.29
[INFO] [stderr]    Compiling version_check v0.9.1
[INFO] [stderr]    Compiling cc v1.0.52
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]     Checking either v1.5.3
[INFO] [stderr]     Checking fnv v1.0.6
[INFO] [stderr]     Checking smallvec v1.4.0
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking itoa v0.4.5
[INFO] [stderr]    Compiling pkg-config v0.3.17
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling ryu v1.0.4
[INFO] [stderr]    Compiling openssl v0.10.29
[INFO] [stderr]     Checking percent-encoding v1.0.1
[INFO] [stderr]    Compiling native-tls v0.2.4
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]     Checking nodrop v0.1.14
[INFO] [stderr]     Checking try-lock v0.2.2
[INFO] [stderr]     Checking ahash v0.3.4
[INFO] [stderr]    Compiling crc32fast v1.2.0
[INFO] [stderr]     Checking regex-syntax v0.6.17
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]     Checking ppv-lite86 v0.2.6
[INFO] [stderr]     Checking bytes v0.5.4
[INFO] [stderr]    Compiling encoding_rs v0.8.22
[INFO] [stderr]     Checking adler32 v1.0.4
[INFO] [stderr]     Checking static_assertions v0.3.4
[INFO] [stderr]     Checking dtoa v0.4.5
[INFO] [stderr]    Compiling libloading v0.6.2
[INFO] [stderr]     Checking lazycell v1.2.1
[INFO] [stderr]     Checking base64 v0.11.0
[INFO] [stderr]     Checking utf-8 v0.7.5
[INFO] [stderr]    Compiling memoffset v0.5.4
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]    Compiling indexmap v1.3.2
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]     Checking memchr v2.3.3
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]     Checking smallvec v0.6.13
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling hyper v0.12.35
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]     Checking base64 v0.10.1
[INFO] [stderr]     Checking crossbeam-utils v0.7.2
[INFO] [stderr]     Checking try_from v0.3.2
[INFO] [stderr]     Checking miniz_oxide v0.3.6
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand_jitter v0.1.4
[INFO] [stderr]     Checking unicode-normalization v0.1.12
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling error-chain v0.12.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]     Checking http v0.2.1
[INFO] [stderr]     Checking input_buffer v0.3.1
[INFO] [stderr]     Checking crossbeam-queue v0.2.1
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking crossbeam-channel v0.4.2
[INFO] [stderr]     Checking tokio-executor v0.1.10
[INFO] [stderr]     Checking tokio-sync v0.1.8
[INFO] [stderr]     Checking want v0.2.0
[INFO] [stderr]    Compiling openssl-sys v0.9.55
[INFO] [stderr]    Compiling backtrace-sys v0.1.37
[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/hashbrown-0.7.2/src/lib.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 | /     feature(
[INFO] [stdout] 16 | |         alloc_layout_extra,
[INFO] [stdout] 17 | |         allocator_api,
[INFO] [stdout] 18 | |         ptr_offset_from,
[INFO] [stdout] ...  |
[INFO] [stdout] 22 | |         specialization,
[INFO] [stdout] 23 | |     )
[INFO] [stdout]    | |_____^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking regex v1.3.7
[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 `hashbrown`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "7aa585fba0dbe5010acb22a7e119acce55cfaf338d3166611603db9131ef3bbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7aa585fba0dbe5010acb22a7e119acce55cfaf338d3166611603db9131ef3bbe", kill_on_drop: false }`
[INFO] [stdout] 7aa585fba0dbe5010acb22a7e119acce55cfaf338d3166611603db9131ef3bbe
