[INFO] cloning repository https://github.com/lutzer/midi_clock
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/lutzer/midi_clock" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flutzer%2Fmidi_clock", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flutzer%2Fmidi_clock'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d3ebc945086560f6ca5b397deefd9be3c443d17f
[INFO] testing lutzer/midi_clock against 1.54.0 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flutzer%2Fmidi_clock" "/workspace/builds/worker-46/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-46/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lutzer/midi_clock 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] removed /workspace/builds/worker-46/source/.cargo/config
[INFO] started tweaking git repo https://github.com/lutzer/midi_clock
[INFO] finished tweaking git repo https://github.com/lutzer/midi_clock
[INFO] tweaked toml for git repo https://github.com/lutzer/midi_clock written to /workspace/builds/worker-46/source/Cargo.toml
[INFO] crate git repo https://github.com/lutzer/midi_clock already has a lockfile, it will not be regenerated
[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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/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] [stdout] 2c722e8d15691539b5228792d82995b9346031f6dc3688781b1e8ca058f08c38
[INFO] running `Command { std: "docker" "start" "-a" "2c722e8d15691539b5228792d82995b9346031f6dc3688781b1e8ca058f08c38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2c722e8d15691539b5228792d82995b9346031f6dc3688781b1e8ca058f08c38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2c722e8d15691539b5228792d82995b9346031f6dc3688781b1e8ca058f08c38", kill_on_drop: false }`
[INFO] [stdout] 2c722e8d15691539b5228792d82995b9346031f6dc3688781b1e8ca058f08c38
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/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] f8a38d9cc8bd7ea506695b53a7fbdddccac7a1f53587808ca0b3a7c5be1da062
[INFO] running `Command { std: "docker" "start" "-a" "f8a38d9cc8bd7ea506695b53a7fbdddccac7a1f53587808ca0b3a7c5be1da062", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.28
[INFO] [stderr]    Compiling stable_deref_trait v1.2.0
[INFO] [stderr]    Compiling semver v1.0.3
[INFO] [stderr]    Compiling cortex-m v0.7.3
[INFO] [stderr]    Compiling nb v1.0.0
[INFO] [stderr]    Compiling syn v1.0.74
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling vcell v0.1.3
[INFO] [stderr]    Compiling cortex-m v0.6.7
[INFO] [stderr]    Compiling bitfield v0.13.2
[INFO] [stderr]    Compiling cortex-m-rt v0.6.15
[INFO] [stderr]    Compiling r0 v0.2.2
[INFO] [stderr]    Compiling stm32f1 v0.11.0
[INFO] [stderr]    Compiling heapless v0.7.3
[INFO] [stderr]    Compiling linked_list_allocator v0.8.11
[INFO] [stderr]    Compiling panic-halt v0.2.0
[INFO] [stderr]    Compiling hash32 v0.2.1
[INFO] [stderr]    Compiling generic-array v0.13.3
[INFO] [stderr]    Compiling generic-array v0.12.4
[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/linked_list_allocator-0.8.11/src/lib.rs:1:41
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![cfg_attr(feature = "const_mut_refs", feature(const_mut_refs))]
[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 `linked_list_allocator`
[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" "f8a38d9cc8bd7ea506695b53a7fbdddccac7a1f53587808ca0b3a7c5be1da062", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f8a38d9cc8bd7ea506695b53a7fbdddccac7a1f53587808ca0b3a7c5be1da062", kill_on_drop: false }`
[INFO] [stdout] f8a38d9cc8bd7ea506695b53a7fbdddccac7a1f53587808ca0b3a7c5be1da062
