[INFO] fetching crate mech-server 0.0.4...
[INFO] checking mech-server-0.0.4 against 1.55.0 for beta-1.56-3
[INFO] extracting crate mech-server 0.0.4 into /workspace/builds/worker-75/source
[INFO] validating manifest of crates.io crate mech-server 0.0.4 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", 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-75/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "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 term v0.4.6
[INFO] [stderr]   Downloaded term-painter v0.2.4
[INFO] [stderr]   Downloaded iron v0.6.1
[INFO] [stderr]   Downloaded mount v0.4.0
[INFO] [stderr]   Downloaded staticfile v0.5.0
[INFO] [stderr]   Downloaded bincode v0.8.0
[INFO] [stderr]   Downloaded sequence_trie v0.3.6
[INFO] [stderr]   Downloaded mech-syntax v0.0.4
[INFO] [stderr]   Downloaded mech-program v0.0.4
[INFO] [stderr]   Downloaded mech-core v0.0.4
[INFO] [stderr]   Downloaded mech-utilities v0.0.4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-75/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-75/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1301436692dbc07c7e2f54713b7cffd1478efb798714f9b2983cb925ec0d6b48
[INFO] running `Command { std: "docker" "start" "-a" "1301436692dbc07c7e2f54713b7cffd1478efb798714f9b2983cb925ec0d6b48", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1301436692dbc07c7e2f54713b7cffd1478efb798714f9b2983cb925ec0d6b48", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1301436692dbc07c7e2f54713b7cffd1478efb798714f9b2983cb925ec0d6b48", kill_on_drop: false }`
[INFO] [stdout] 1301436692dbc07c7e2f54713b7cffd1478efb798714f9b2983cb925ec0d6b48
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-75/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-75/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c1d909752f537410d259e35c0cc99543870b18d19ca884e4130ed609adbd916b
[INFO] running `Command { std: "docker" "start" "-a" "c1d909752f537410d259e35c0cc99543870b18d19ca884e4130ed609adbd916b", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking futures v0.1.31
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling syn v1.0.80
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling siphasher v0.2.3
[INFO] [stderr]     Checking itoa v0.4.8
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling openssl v0.10.36
[INFO] [stderr]     Checking gimli v0.25.0
[INFO] [stderr]     Checking ahash v0.3.8
[INFO] [stderr]    Compiling native-tls v0.2.8
[INFO] [stderr]     Checking rustc-demangle v0.1.21
[INFO] [stderr]     Checking openssl-probe v0.1.4
[INFO] [stderr]     Checking modifier v0.1.0
[INFO] [stderr]     Checking dtoa v0.4.8
[INFO] [stderr]     Checking sequence_trie v0.3.6
[INFO] [stderr]     Checking unicode-width v0.1.9
[INFO] [stderr]     Checking same-file v0.1.3
[INFO] [stderr]     Checking term v0.4.6
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling openssl-sys v0.9.67
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]    Compiling backtrace v0.3.61
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]     Checking unsafe-any v0.4.2
[INFO] [stderr]    Compiling nom v5.1.2
[INFO] [stderr]    Compiling libloading v0.5.2
[INFO] [stderr]     Checking try_from v0.3.2
[INFO] [stderr]     Checking base64 v0.10.1
[INFO] [stderr]     Checking time v0.1.44
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]     Checking idna v0.1.5
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]     Checking smallvec v0.6.14
[INFO] [stderr]     Checking object v0.26.2
[INFO] [stderr]    Compiling hyper v0.12.36
[INFO] [stderr]     Checking generic-array v0.12.4
[INFO] [stderr]     Checking flate2 v1.0.22
[INFO] [stderr]     Checking num-traits v0.1.43
[INFO] [stderr]     Checking mio-extras v2.0.6
[INFO] [stderr]     Checking publicsuffix v1.5.6
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking typemap v0.3.3
[INFO] [stderr]     Checking walkdir v1.0.7
[INFO] [stderr]     Checking phf_shared v0.7.24
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]     Checking block-buffer v0.7.3
[INFO] [stderr]     Checking digest v0.8.1
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]     Checking phf v0.7.24
[INFO] [stderr]     Checking term-painter v0.2.4
[INFO] [stderr]     Checking http v0.1.21
[INFO] [stderr]     Checking string v0.2.1
[INFO] [stderr]     Checking url v1.7.2
[INFO] [stderr]     Checking plugin v0.2.6
[INFO] [stderr]     Checking sha-1 v0.8.2
[INFO] [stderr]     Checking tokio-io v0.1.13
[INFO] [stderr]     Checking tokio-sync v0.1.8
[INFO] [stderr]     Checking tokio-buf v0.1.1
[INFO] [stderr]     Checking futures-cpupool v0.1.8
[INFO] [stderr]     Checking want v0.2.0
[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 ws v0.9.1
[INFO] [stderr] error: could not compile `hashbrown` due to 2 previous errors
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "c1d909752f537410d259e35c0cc99543870b18d19ca884e4130ed609adbd916b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c1d909752f537410d259e35c0cc99543870b18d19ca884e4130ed609adbd916b", kill_on_drop: false }`
[INFO] [stdout] c1d909752f537410d259e35c0cc99543870b18d19ca884e4130ed609adbd916b
