[INFO] fetching crate mech-syntax 0.0.5...
[INFO] testing mech-syntax-0.0.5 against 1.54.0 for beta-1.55-1
[INFO] extracting crate mech-syntax 0.0.5 into /workspace/builds/worker-35/source
[INFO] validating manifest of crates.io crate mech-syntax 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-syntax 0.0.5
[INFO] finished tweaking crates.io crate mech-syntax 0.0.5
[INFO] tweaked toml for crates.io crate mech-syntax 0.0.5 written to /workspace/builds/worker-35/source/Cargo.toml
[INFO] crate crates.io crate mech-syntax 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 lexical-core v0.6.7
[INFO] [stderr]   Downloaded ahash v0.3.4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-35/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-35/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] 228e83be735f6807c7128e50db3c22347251baf209110b8335b5e57ab9441303
[INFO] running `Command { std: "docker" "start" "-a" "228e83be735f6807c7128e50db3c22347251baf209110b8335b5e57ab9441303", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "228e83be735f6807c7128e50db3c22347251baf209110b8335b5e57ab9441303", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "228e83be735f6807c7128e50db3c22347251baf209110b8335b5e57ab9441303", kill_on_drop: false }`
[INFO] [stdout] 228e83be735f6807c7128e50db3c22347251baf209110b8335b5e57ab9441303
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-35/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-35/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" "RUSTFLAGS=--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" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1a440e44f17476448b9467e492d99018ec12f8c73effb4f3eec4a323a581bc1e
[INFO] running `Command { std: "docker" "start" "-a" "1a440e44f17476448b9467e492d99018ec12f8c73effb4f3eec4a323a581bc1e", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling ryu v1.0.4
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling nodrop v0.1.14
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling version_check v0.9.1
[INFO] [stderr]    Compiling cfg-if v0.1.9
[INFO] [stderr]    Compiling ahash v0.3.4
[INFO] [stderr]    Compiling static_assertions v0.3.4
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]    Compiling quote v1.0.4
[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] [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" "1a440e44f17476448b9467e492d99018ec12f8c73effb4f3eec4a323a581bc1e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1a440e44f17476448b9467e492d99018ec12f8c73effb4f3eec4a323a581bc1e", kill_on_drop: false }`
[INFO] [stdout] 1a440e44f17476448b9467e492d99018ec12f8c73effb4f3eec4a323a581bc1e
