[INFO] fetching crate canonical_host 0.5.0...
[INFO] testing canonical_host-0.5.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate canonical_host 0.5.0 into /workspace/builds/worker-48/source
[INFO] validating manifest of crates.io crate canonical_host 0.5.0 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 canonical_host 0.5.0
[INFO] finished tweaking crates.io crate canonical_host 0.5.0
[INFO] tweaked toml for crates.io crate canonical_host 0.5.0 written to /workspace/builds/worker-48/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/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] 4bae106d77ec293e2014b797a022f8471674eb469e1a2db15a16e86f348c2594
[INFO] running `Command { std: "docker" "start" "-a" "4bae106d77ec293e2014b797a022f8471674eb469e1a2db15a16e86f348c2594", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4bae106d77ec293e2014b797a022f8471674eb469e1a2db15a16e86f348c2594", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4bae106d77ec293e2014b797a022f8471674eb469e1a2db15a16e86f348c2594", kill_on_drop: false }`
[INFO] [stdout] 4bae106d77ec293e2014b797a022f8471674eb469e1a2db15a16e86f348c2594
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-48/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] 591f15ee925878041176caa581e7ac946f83f58db846fd3ad7f6bb94dc403cf4
[INFO] running `Command { std: "docker" "start" "-a" "591f15ee925878041176caa581e7ac946f83f58db846fd3ad7f6bb94dc403cf4", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling nodrop v0.1.14
[INFO] [stderr]    Compiling stable_deref_trait v1.2.0
[INFO] [stderr]    Compiling scopeguard v0.3.3
[INFO] [stderr]    Compiling byteorder v1.4.3
[INFO] [stderr]    Compiling arrayref v0.3.6
[INFO] [stderr]    Compiling ppv-lite86 v0.2.10
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]    Compiling constant_time_eq v0.1.5
[INFO] [stderr]    Compiling arrayvec v0.5.2
[INFO] [stderr]    Compiling smallvec v1.6.1
[INFO] [stderr]    Compiling scopeguard v1.1.0
[INFO] [stderr]    Compiling seahash v3.0.7
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling remove_dir_all v0.5.3
[INFO] [stderr]    Compiling instant v0.1.10
[INFO] [stderr]    Compiling owning_ref v0.4.1
[INFO] [stderr]    Compiling lock_api v0.4.5
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling lock_api v0.1.5
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling smallvec v0.6.14
[INFO] [stderr]    Compiling parking_lot_core v0.4.0
[INFO] [stderr]    Compiling blake2b_simd v0.3.1
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling getrandom v0.2.3
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling memmap v0.7.0
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.4
[INFO] [stderr]    Compiling parking_lot v0.7.1
[INFO] [stderr]    Compiling tempfile v3.2.0
[INFO] [stderr]    Compiling appendix v0.2.1
[INFO] [stderr]    Compiling synstructure v0.12.5
[INFO] [stderr]    Compiling derive_arbitrary v0.3.3
[INFO] [stderr]    Compiling arbitrary v0.3.3
[INFO] [stderr]    Compiling canonical v0.5.3
[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/canonical-0.5.3/src/lib.rs:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![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 `canonical` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "591f15ee925878041176caa581e7ac946f83f58db846fd3ad7f6bb94dc403cf4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "591f15ee925878041176caa581e7ac946f83f58db846fd3ad7f6bb94dc403cf4", kill_on_drop: false }`
[INFO] [stdout] 591f15ee925878041176caa581e7ac946f83f58db846fd3ad7f6bb94dc403cf4