[INFO] fetching crate alloc-cortex-m 0.4.2...
[INFO] testing alloc-cortex-m-0.4.2 against 1.60.0 for beta-1.61-1
[INFO] extracting crate alloc-cortex-m 0.4.2 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate alloc-cortex-m 0.4.2 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate alloc-cortex-m 0.4.2
[INFO] finished tweaking crates.io crate alloc-cortex-m 0.4.2
[INFO] tweaked toml for crates.io crate alloc-cortex-m 0.4.2 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate alloc-cortex-m 0.4.2 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded linked_list_allocator v0.8.11
[INFO] [stderr]   Downloaded syn v1.0.58
[INFO] [stderr]   Downloaded cortex-m-rt-macros v0.1.8
[INFO] [stderr]   Downloaded volatile-register v0.2.0
[INFO] [stderr]   Downloaded cortex-m-rt v0.6.13
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 38d647d2fd5646e5c040332fe72ff3e028b4c1c2a980978e12694063450e3705
[INFO] running `Command { std: "docker" "start" "-a" "38d647d2fd5646e5c040332fe72ff3e028b4c1c2a980978e12694063450e3705", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "38d647d2fd5646e5c040332fe72ff3e028b4c1c2a980978e12694063450e3705", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "38d647d2fd5646e5c040332fe72ff3e028b4c1c2a980978e12694063450e3705", kill_on_drop: false }`
[INFO] [stdout] 38d647d2fd5646e5c040332fe72ff3e028b4c1c2a980978e12694063450e3705
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 477a8258dc9034f4196449dad9664127a2536a482f020995c4f4ffb39125feca
[INFO] running `Command { std: "docker" "start" "-a" "477a8258dc9034f4196449dad9664127a2536a482f020995c4f4ffb39125feca", kill_on_drop: false }`
[INFO] [stderr]    Compiling nb v1.0.0
[INFO] [stderr]    Compiling cortex-m v0.7.4
[INFO] [stderr]    Compiling vcell v0.1.3
[INFO] [stderr]    Compiling bitfield v0.13.2
[INFO] [stderr]    Compiling linked_list_allocator v0.8.11
[INFO] [stderr]    Compiling bare-metal v0.2.5
[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] [stderr]    Compiling volatile-register v0.2.0
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `linked_list_allocator` due to 2 previous errors
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "477a8258dc9034f4196449dad9664127a2536a482f020995c4f4ffb39125feca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "477a8258dc9034f4196449dad9664127a2536a482f020995c4f4ffb39125feca", kill_on_drop: false }`
[INFO] [stdout] 477a8258dc9034f4196449dad9664127a2536a482f020995c4f4ffb39125feca