[INFO] fetching crate yolk 0.6.0...
[INFO] testing yolk-0.6.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate yolk 0.6.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate yolk 0.6.0 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 yolk 0.6.0
[INFO] finished tweaking crates.io crate yolk 0.6.0
[INFO] tweaked toml for crates.io crate yolk 0.6.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate crates.io crate yolk 0.6.0 already has a lockfile, it will not be regenerated
[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]  Downloading crates ...
[INFO] [stderr]   Downloaded pest_meta v2.1.1
[INFO] [stderr]   Downloaded pest v2.1.1
[INFO] [stderr]   Downloaded pest_generator v2.1.0
[INFO] [stderr]   Downloaded yolol_number v0.7.0
[INFO] [stderr]   Downloaded yolol_number v0.6.2
[INFO] [stderr]   Downloaded cylon_ast v0.3.2
[INFO] [stderr]   Downloaded yoloxide v0.4.3
[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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d094e41fe5a20d5670012d7c62eee95f338a949444eb38adf6f913be4c67816e
[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" "d094e41fe5a20d5670012d7c62eee95f338a949444eb38adf6f913be4c67816e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d094e41fe5a20d5670012d7c62eee95f338a949444eb38adf6f913be4c67816e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d094e41fe5a20d5670012d7c62eee95f338a949444eb38adf6f913be4c67816e", kill_on_drop: false }`
[INFO] [stdout] d094e41fe5a20d5670012d7c62eee95f338a949444eb38adf6f913be4c67816e
[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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bbd678ed4c0f60869d78d1c132a21fe4e8f9defa0245affdbb4e3697a54d4755
[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" "bbd678ed4c0f60869d78d1c132a21fe4e8f9defa0245affdbb4e3697a54d4755", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling ucd-trie v0.1.2
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling regex v1.2.1
[INFO] [stderr]    Compiling pest v2.1.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.31
[INFO] [stderr]    Compiling atty v0.2.13
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling backtrace v0.3.35
[INFO] [stderr]    Compiling pest_meta v2.1.1
[INFO] [stderr]    Compiling failure v0.1.5
[INFO] [stderr]    Compiling pest_generator v2.1.0
[INFO] [stderr]    Compiling pest_derive v2.1.0
[INFO] [stderr]    Compiling serde_derive v1.0.99
[INFO] [stderr]    Compiling serde v1.0.99
[INFO] [stderr]    Compiling serde_json v1.0.40
[INFO] [stderr]    Compiling yolol_number v0.7.0
[INFO] [stderr]    Compiling yolol_number v0.6.2
[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/yolol_number-0.7.0/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[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/yolol_number-0.6.2/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(trait_alias)]
[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 `yolol_number` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[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: build failed
[INFO] running `Command { std: "docker" "inspect" "bbd678ed4c0f60869d78d1c132a21fe4e8f9defa0245affdbb4e3697a54d4755", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bbd678ed4c0f60869d78d1c132a21fe4e8f9defa0245affdbb4e3697a54d4755", kill_on_drop: false }`
[INFO] [stdout] bbd678ed4c0f60869d78d1c132a21fe4e8f9defa0245affdbb4e3697a54d4755