[INFO] fetching crate mech-server 0.0.4...
[INFO] documenting mech-server-0.0.4 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate mech-server 0.0.4 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate mech-server 0.0.4 on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mech-server 0.0.4
[INFO] finished tweaking crates.io crate mech-server 0.0.4
[INFO] tweaked toml for crates.io crate mech-server 0.0.4 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded mech-utilities v0.0.4
[INFO] [stderr]   Downloaded mech-core v0.0.4
[INFO] [stderr]   Downloaded mech-syntax v0.0.4
[INFO] [stderr]   Downloaded mech-program v0.0.4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f150a9dfc31eab0a2db6b4a70c05b65210760b6f25e1c249488bb587d7b9f145
[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" "f150a9dfc31eab0a2db6b4a70c05b65210760b6f25e1c249488bb587d7b9f145", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f150a9dfc31eab0a2db6b4a70c05b65210760b6f25e1c249488bb587d7b9f145", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f150a9dfc31eab0a2db6b4a70c05b65210760b6f25e1c249488bb587d7b9f145", kill_on_drop: false }`
[INFO] [stdout] f150a9dfc31eab0a2db6b4a70c05b65210760b6f25e1c249488bb587d7b9f145
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c9defe4edec6308e0f102ac1f10043aad64cc8c21a4b2e17f1cb0b673980ac45
[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" "c9defe4edec6308e0f102ac1f10043aad64cc8c21a4b2e17f1cb0b673980ac45", 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 serde v1.0.115
[INFO] [stderr]     Checking sequence_trie v0.3.6
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]     Checking want v0.2.0
[INFO] [stderr]     Checking tokio-io v0.1.13
[INFO] [stderr]     Checking mio-extras v2.0.6
[INFO] [stderr]     Checking publicsuffix v1.5.4
[INFO] [stderr]     Checking native-tls v0.2.4
[INFO] [stderr]     Checking iron v0.6.1
[INFO] [stderr]     Checking ws v0.9.1
[INFO] [stderr]     Checking mount v0.4.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta 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 staticfile v0.5.0
[INFO] [stderr]     Checking tokio-reactor v0.1.12
[INFO] [stderr]     Checking h2 v0.1.26
[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" "c9defe4edec6308e0f102ac1f10043aad64cc8c21a4b2e17f1cb0b673980ac45", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c9defe4edec6308e0f102ac1f10043aad64cc8c21a4b2e17f1cb0b673980ac45", kill_on_drop: false }`
[INFO] [stdout] c9defe4edec6308e0f102ac1f10043aad64cc8c21a4b2e17f1cb0b673980ac45