[INFO] fetching crate keebrs 0.3.0...
[INFO] testing keebrs-0.3.0 against 1.54.0 for beta-1.55-1
[INFO] extracting crate keebrs 0.3.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate keebrs 0.3.0 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 keebrs 0.3.0
[INFO] finished tweaking crates.io crate keebrs 0.3.0
[INFO] tweaked toml for crates.io crate keebrs 0.3.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] b1eb9d27c0786b0e5665346c1d68876374878f1aca84aee6db041ad9b62bd2cd
[INFO] running `Command { std: "docker" "start" "-a" "b1eb9d27c0786b0e5665346c1d68876374878f1aca84aee6db041ad9b62bd2cd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b1eb9d27c0786b0e5665346c1d68876374878f1aca84aee6db041ad9b62bd2cd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b1eb9d27c0786b0e5665346c1d68876374878f1aca84aee6db041ad9b62bd2cd", kill_on_drop: false }`
[INFO] [stdout] b1eb9d27c0786b0e5665346c1d68876374878f1aca84aee6db041ad9b62bd2cd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] 77d402fa568915b502a7809a717d04fdd835e1c2395c5cf9fa42bcacb50beb4c
[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" "77d402fa568915b502a7809a717d04fdd835e1c2395c5cf9fa42bcacb50beb4c", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling futures-core v0.3.16
[INFO] [stderr]    Compiling futures-task v0.3.16
[INFO] [stderr]    Compiling futures-channel v0.3.16
[INFO] [stderr]    Compiling serde v1.0.127
[INFO] [stderr]    Compiling futures-sink v0.3.16
[INFO] [stderr]    Compiling heapless v0.5.6
[INFO] [stderr]    Compiling usb-device v0.2.8
[INFO] [stderr]    Compiling futures-util v0.3.16
[INFO] [stderr]    Compiling hash32 v0.1.1
[INFO] [stderr]    Compiling nb v0.1.3
[INFO] [stderr]    Compiling smart-leds-trait v0.2.1
[INFO] [stderr]    Compiling pin-project-internal v0.4.28
[INFO] [stderr]    Compiling derive-newtype v0.2.3
[INFO] [stderr]    Compiling embedded-hal v0.2.6
[INFO] [stderr]    Compiling smart-leds v0.3.0
[INFO] [stderr]    Compiling polymer-core v0.1.0
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/polymer-core-0.1.0/src/lib.rs:2:34
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(arbitrary_self_types, const_fn, never_type)]
[INFO] [stdout]   |                                  ^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: split into finer-grained feature gates
[INFO] [stdout] 
[INFO] [stdout] 
[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/polymer-core-0.1.0/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(arbitrary_self_types, const_fn, never_type)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `polymer-core`
[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" "77d402fa568915b502a7809a717d04fdd835e1c2395c5cf9fa42bcacb50beb4c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "77d402fa568915b502a7809a717d04fdd835e1c2395c5cf9fa42bcacb50beb4c", kill_on_drop: false }`
[INFO] [stdout] 77d402fa568915b502a7809a717d04fdd835e1c2395c5cf9fa42bcacb50beb4c
