[INFO] fetching crate stepper-driver 0.1.0...
[INFO] testing stepper-driver-0.1.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate stepper-driver 0.1.0 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate stepper-driver 0.1.0 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 stepper-driver 0.1.0
[INFO] finished tweaking crates.io crate stepper-driver 0.1.0
[INFO] tweaked toml for crates.io crate stepper-driver 0.1.0 written to /workspace/builds/worker-10/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] e3b2b2d8574f1ed105b314d5d7280b3a6b267d0aec8a209643a1fd0416725dfc
[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" "e3b2b2d8574f1ed105b314d5d7280b3a6b267d0aec8a209643a1fd0416725dfc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e3b2b2d8574f1ed105b314d5d7280b3a6b267d0aec8a209643a1fd0416725dfc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e3b2b2d8574f1ed105b314d5d7280b3a6b267d0aec8a209643a1fd0416725dfc", kill_on_drop: false }`
[INFO] [stdout] e3b2b2d8574f1ed105b314d5d7280b3a6b267d0aec8a209643a1fd0416725dfc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] [stdout] fc5cf2efb3f247cabc146bddcb5d4ba673c8b0d86ae18c5c19ec3e0620a1ac60
[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" "fc5cf2efb3f247cabc146bddcb5d4ba673c8b0d86ae18c5c19ec3e0620a1ac60", kill_on_drop: false }`
[INFO] [stderr]    Compiling embedded-hal v0.2.4
[INFO] [stderr]    Compiling embedded-hal v0.1.3
[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/embedded-hal-0.1.3/src/lib.rs:681:1
[INFO] [stdout]     |
[INFO] [stdout] 681 | #![feature(never_type)]
[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 `embedded-hal`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "fc5cf2efb3f247cabc146bddcb5d4ba673c8b0d86ae18c5c19ec3e0620a1ac60", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fc5cf2efb3f247cabc146bddcb5d4ba673c8b0d86ae18c5c19ec3e0620a1ac60", kill_on_drop: false }`
[INFO] [stdout] fc5cf2efb3f247cabc146bddcb5d4ba673c8b0d86ae18c5c19ec3e0620a1ac60