[INFO] fetching crate juliex 0.3.0-alpha.8...
[INFO] documenting juliex-0.3.0-alpha.8 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate juliex 0.3.0-alpha.8 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate juliex 0.3.0-alpha.8 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 juliex 0.3.0-alpha.8
[INFO] finished tweaking crates.io crate juliex 0.3.0-alpha.8
[INFO] tweaked toml for crates.io crate juliex 0.3.0-alpha.8 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate crates.io crate juliex 0.3.0-alpha.8 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 8e5d2a7f0b1b5036612a7a856195385a3a90149f28c2dc1ed955b09db0b3e21e
[INFO] running `Command { std: "docker" "start" "-a" "8e5d2a7f0b1b5036612a7a856195385a3a90149f28c2dc1ed955b09db0b3e21e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8e5d2a7f0b1b5036612a7a856195385a3a90149f28c2dc1ed955b09db0b3e21e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8e5d2a7f0b1b5036612a7a856195385a3a90149f28c2dc1ed955b09db0b3e21e", kill_on_drop: false }`
[INFO] [stdout] 8e5d2a7f0b1b5036612a7a856195385a3a90149f28c2dc1ed955b09db0b3e21e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 0f4d5a9723661923471433f015d6a92f031232f149ef8ec0c31ad7b16dac7e70
[INFO] running `Command { std: "docker" "start" "-a" "0f4d5a9723661923471433f015d6a92f031232f149ef8ec0c31ad7b16dac7e70", 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]     Checking lazy_static v1.2.0
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]     Checking ppv-lite86 v0.2.5
[INFO] [stderr]     Checking cfg-if v0.1.6
[INFO] [stderr]    Compiling proc-macro-nested v0.1.3
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling arrayvec v0.4.10
[INFO] [stderr]     Checking nodrop v0.1.13
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking pin-utils v0.1.0-alpha.4
[INFO] [stderr]     Checking scopeguard v1.0.0
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling memoffset v0.5.1
[INFO] [stderr]     Checking crossbeam-utils v0.6.6
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking c2-chacha v0.2.2
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking crossbeam-queue v0.1.2
[INFO] [stderr]     Checking crossbeam-channel v0.3.9
[INFO] [stderr]     Checking crossbeam-epoch v0.7.2
[INFO] [stderr]     Checking getrandom v0.1.3
[INFO] [stderr]     Checking num_cpus v1.10.0
[INFO] [stderr]     Checking crossbeam-deque v0.7.1
[INFO] [stderr]     Checking rand_core v0.5.0
[INFO] [stderr]     Checking crossbeam v0.7.2
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.0
[INFO] [stderr]    Compiling proc-macro-hack v0.5.7
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.17
[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/futures-util-preview-0.3.0-alpha.17/src/lib.rs:4:38
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "async-await", feature(async_await))]
[INFO] [stdout]   |                                      ^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `async_await` has been stable since 1.39.0 and no longer requires an attribute to enable
[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 `futures-util-preview`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "0f4d5a9723661923471433f015d6a92f031232f149ef8ec0c31ad7b16dac7e70", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0f4d5a9723661923471433f015d6a92f031232f149ef8ec0c31ad7b16dac7e70", kill_on_drop: false }`
[INFO] [stdout] 0f4d5a9723661923471433f015d6a92f031232f149ef8ec0c31ad7b16dac7e70
