[INFO] fetching crate mech-program 0.0.5...
[INFO] documenting mech-program-0.0.5 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate mech-program 0.0.5 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate mech-program 0.0.5 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 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-12/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" "+1.46.0" "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-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] e3b95583e056425d6ec2a59acbf370563f0ef3f08a178ad72520c98c7f0505e8
[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" "e3b95583e056425d6ec2a59acbf370563f0ef3f08a178ad72520c98c7f0505e8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e3b95583e056425d6ec2a59acbf370563f0ef3f08a178ad72520c98c7f0505e8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e3b95583e056425d6ec2a59acbf370563f0ef3f08a178ad72520c98c7f0505e8", kill_on_drop: false }`
[INFO] [stdout] e3b95583e056425d6ec2a59acbf370563f0ef3f08a178ad72520c98c7f0505e8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] 829253fd4547496b64fa79c0411592bcef2a8a56d27d806023886b4101f2801a
[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" "829253fd4547496b64fa79c0411592bcef2a8a56d27d806023886b4101f2801a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]     Checking ahash v0.3.4
[INFO] [stderr]    Compiling backtrace-sys v0.1.37
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling error-chain v0.12.2
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]     Checking tokio-sync v0.1.8
[INFO] [stderr]     Checking try_from v0.3.2
[INFO] [stderr]     Checking log v0.4.8
[INFO] [stderr]     Checking idna v0.1.5
[INFO] [stderr]     Checking net2 v0.2.34
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]     Checking futures-cpupool v0.1.8
[INFO] [stderr]     Checking flate2 v1.0.14
[INFO] [stderr]     Checking colored v1.9.3
[INFO] [stderr]     Checking openssl v0.10.29
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking parking_lot_core v0.6.2
[INFO] [stderr]     Checking want v0.2.0
[INFO] [stderr]     Checking tokio-executor v0.1.10
[INFO] [stderr]     Checking crossbeam-epoch v0.8.2
[INFO] [stderr]     Checking crossbeam-queue v0.2.1
[INFO] [stderr]     Checking crossbeam-channel v0.4.2
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking publicsuffix v1.5.4
[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 parking_lot v0.9.0
[INFO] [stderr]     Checking tokio-current-thread v0.1.7
[INFO] [stderr]     Checking tokio-timer v0.2.13
[INFO] [stderr]     Checking url v1.7.2
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking tokio-io v0.1.13
[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" "829253fd4547496b64fa79c0411592bcef2a8a56d27d806023886b4101f2801a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "829253fd4547496b64fa79c0411592bcef2a8a56d27d806023886b4101f2801a", kill_on_drop: false }`
[INFO] [stdout] 829253fd4547496b64fa79c0411592bcef2a8a56d27d806023886b4101f2801a