[INFO] fetching crate enso-flexer 0.1.3...
[INFO] testing enso-flexer-0.1.3 against 1.49.0 for beta-1.50-1
[INFO] extracting crate enso-flexer 0.1.3 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate enso-flexer 0.1.3 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate enso-flexer 0.1.3
[INFO] finished tweaking crates.io crate enso-flexer 0.1.3
[INFO] tweaked toml for crates.io crate enso-flexer 0.1.3 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--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-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 243c4f3c4c2ebe6c00bcaaa4fbab40cb118f0ef71fecf1859335ed135c490531
[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" "243c4f3c4c2ebe6c00bcaaa4fbab40cb118f0ef71fecf1859335ed135c490531", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "243c4f3c4c2ebe6c00bcaaa4fbab40cb118f0ef71fecf1859335ed135c490531", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "243c4f3c4c2ebe6c00bcaaa4fbab40cb118f0ef71fecf1859335ed135c490531", kill_on_drop: false }`
[INFO] [stdout] 243c4f3c4c2ebe6c00bcaaa4fbab40cb118f0ef71fecf1859335ed135c490531
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", 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] 762221e0156e466cf3f1ff65761df5ec2cdd31a3741ef107083fcf7ad4d223ac
[INFO] running `Command { std: "docker" "start" "-a" "762221e0156e466cf3f1ff65761df5ec2cdd31a3741ef107083fcf7ad4d223ac", kill_on_drop: false }`
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.58
[INFO] [stderr]    Compiling wasm-bindgen v0.2.58
[INFO] [stderr]    Compiling sourcefile v0.1.4
[INFO] [stderr]    Compiling boolinator v2.4.0
[INFO] [stderr]    Compiling rawpointer v0.2.1
[INFO] [stderr]    Compiling weak-table v0.2.4
[INFO] [stderr]    Compiling enclose v1.1.8
[INFO] [stderr]    Compiling nonempty v0.1.5
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling nom v4.2.3
[INFO] [stderr]    Compiling libm v0.2.1
[INFO] [stderr]    Compiling generic-array v0.13.2
[INFO] [stderr]    Compiling paste v0.1.18
[INFO] [stderr]    Compiling enso-macro-utils v0.1.1
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling shrinkwraprs v0.3.0
[INFO] [stderr]    Compiling ifmt-impl v0.2.0
[INFO] [stderr]    Compiling derivative v1.0.4
[INFO] [stderr]    Compiling rand_distr v0.2.2
[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/enso-macro-utils-0.1.1/src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling matrixmultiply v0.2.4
[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 `enso-macro-utils`
[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" "762221e0156e466cf3f1ff65761df5ec2cdd31a3741ef107083fcf7ad4d223ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "762221e0156e466cf3f1ff65761df5ec2cdd31a3741ef107083fcf7ad4d223ac", kill_on_drop: false }`
[INFO] [stdout] 762221e0156e466cf3f1ff65761df5ec2cdd31a3741ef107083fcf7ad4d223ac