[INFO] fetching crate guff-matrix 0.1.12...
[INFO] testing guff-matrix-0.1.12 against 1.55.0 for beta-1.56-1
[INFO] extracting crate guff-matrix 0.1.12 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate guff-matrix 0.1.12 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 guff-matrix 0.1.12
[INFO] finished tweaking crates.io crate guff-matrix 0.1.12
[INFO] tweaked toml for crates.io crate guff-matrix 0.1.12 written to /workspace/builds/worker-2/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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] c01883a60cd651efcecf73968bec38b521ae196cdcb1e808f9209402903e722f
[INFO] running `Command { std: "docker" "start" "-a" "c01883a60cd651efcecf73968bec38b521ae196cdcb1e808f9209402903e722f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c01883a60cd651efcecf73968bec38b521ae196cdcb1e808f9209402903e722f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c01883a60cd651efcecf73968bec38b521ae196cdcb1e808f9209402903e722f", kill_on_drop: false }`
[INFO] [stdout] c01883a60cd651efcecf73968bec38b521ae196cdcb1e808f9209402903e722f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] b779d3d24efb5c4f7da2145aa4ec17dec1bdf099dbe23f0a9beb08c8f4b4352f
[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" "b779d3d24efb5c4f7da2145aa4ec17dec1bdf099dbe23f0a9beb08c8f4b4352f", kill_on_drop: false }`
[INFO] [stderr]    Compiling num-complex v0.4.0
[INFO] [stderr]    Compiling num-bigint v0.4.2
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling num-rational v0.4.0
[INFO] [stderr]    Compiling num v0.4.0
[INFO] [stderr]    Compiling guff v0.1.7
[INFO] [stderr]    Compiling guff-matrix v0.1.12 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:53:1
[INFO] [stdout]    |
[INFO] [stdout] 53 | #![feature(stdsimd)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `crate::x86::*`
[INFO] [stdout]   --> src/lib.rs:84:9
[INFO] [stdout]    |
[INFO] [stdout] 84 |     use crate::x86::*;
[INFO] [stdout]    |         ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `guff-matrix` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "b779d3d24efb5c4f7da2145aa4ec17dec1bdf099dbe23f0a9beb08c8f4b4352f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b779d3d24efb5c4f7da2145aa4ec17dec1bdf099dbe23f0a9beb08c8f4b4352f", kill_on_drop: false }`
[INFO] [stdout] b779d3d24efb5c4f7da2145aa4ec17dec1bdf099dbe23f0a9beb08c8f4b4352f