[INFO] fetching crate kapiti 0.0.1...
[INFO] testing kapiti-0.0.1 against 1.55.0 for beta-1.56-1
[INFO] extracting crate kapiti 0.0.1 into /workspace/builds/worker-48/source
[INFO] validating manifest of crates.io crate kapiti 0.0.1 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 kapiti 0.0.1
[INFO] finished tweaking crates.io crate kapiti 0.0.1
[INFO] tweaked toml for crates.io crate kapiti 0.0.1 written to /workspace/builds/worker-48/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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/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] 0ca43176668f49551488fe0a79cf182d7b5273cc3b1c27c325e670b75b788090
[INFO] running `Command { std: "docker" "start" "-a" "0ca43176668f49551488fe0a79cf182d7b5273cc3b1c27c325e670b75b788090", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0ca43176668f49551488fe0a79cf182d7b5273cc3b1c27c325e670b75b788090", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0ca43176668f49551488fe0a79cf182d7b5273cc3b1c27c325e670b75b788090", kill_on_drop: false }`
[INFO] [stdout] 0ca43176668f49551488fe0a79cf182d7b5273cc3b1c27c325e670b75b788090
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/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" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8fc0a87a085d467a8a08cdfb8686c731187cf99b0a85e37a3f7b699089a5a07f
[INFO] running `Command { std: "docker" "start" "-a" "8fc0a87a085d467a8a08cdfb8686c731187cf99b0a85e37a3f7b699089a5a07f", 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling slab v0.4.4
[INFO] [stderr]    Compiling scopeguard v1.1.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling tokio-executor v0.2.0-alpha.1
[INFO] [stderr]    Compiling fnv v1.0.7
[INFO] [stderr]    Compiling byteorder v1.4.3
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling protobuf v2.25.1
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling bytes v1.1.0
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling regex-automata v0.1.10
[INFO] [stderr]    Compiling itoa v0.4.8
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling tracing-core v0.1.19
[INFO] [stderr]    Compiling lock_api v0.3.4
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling smallvec v0.6.14
[INFO] [stderr]    Compiling csv-core v0.1.10
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling tokio-current-thread v0.2.0-alpha.1
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling net2 v0.2.37
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling mio v0.6.23
[INFO] [stderr]    Compiling tokio-io v0.2.0-alpha.1
[INFO] [stderr]    Compiling tokio-sync v0.2.0-alpha.1
[INFO] [stderr]    Compiling tokio-codec v0.2.0-alpha.1
[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/tokio-sync-0.2.0-alpha.1/src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![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] [stderr]    Compiling crossbeam-deque v0.7.4
[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 `tokio-sync` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "8fc0a87a085d467a8a08cdfb8686c731187cf99b0a85e37a3f7b699089a5a07f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8fc0a87a085d467a8a08cdfb8686c731187cf99b0a85e37a3f7b699089a5a07f", kill_on_drop: false }`
[INFO] [stdout] 8fc0a87a085d467a8a08cdfb8686c731187cf99b0a85e37a3f7b699089a5a07f