[INFO] updating cached repository cultural-technology/sunzi
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/cultural-technology/sunzi
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/cultural-technology/sunzi" "work/ex/beta-1.38-1/sources/1.37.0/gh/cultural-technology/sunzi"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/cultural-technology/sunzi'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/cultural-technology/sunzi" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cultural-technology/sunzi"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cultural-technology/sunzi'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 480f5ce4e0e50aef60e552ac24a16dd1a6724613
[INFO] sha for GitHub repo cultural-technology/sunzi: 480f5ce4e0e50aef60e552ac24a16dd1a6724613
[INFO] validating manifest of cultural-technology/sunzi on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of cultural-technology/sunzi on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing cultural-technology/sunzi
[INFO] finished frobbing cultural-technology/sunzi
[INFO] frobbed toml for cultural-technology/sunzi written to work/ex/beta-1.38-1/sources/1.37.0/gh/cultural-technology/sunzi/Cargo.toml
[INFO] started frobbing cultural-technology/sunzi
[INFO] finished frobbing cultural-technology/sunzi
[INFO] frobbed toml for cultural-technology/sunzi written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cultural-technology/sunzi/Cargo.toml
[INFO] crate cultural-technology/sunzi already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing cultural-technology/sunzi against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cultural-technology/sunzi:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] a8e91fa87f21f5bd4befd965af9aa68baad74575a4cb7bf2299dd207a093b13d
[INFO] running `"docker" "start" "-a" "a8e91fa87f21f5bd4befd965af9aa68baad74575a4cb7bf2299dd207a093b13d"`
[INFO] [stderr]    Compiling rcmath v0.0.1 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(step_trait)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Add`
[INFO] [stderr]  --> src/math.rs:3:16
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::ops::{Add, Div, Mul, Rem};
[INFO] [stderr]   |                ^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `rcmath`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "a8e91fa87f21f5bd4befd965af9aa68baad74575a4cb7bf2299dd207a093b13d"`
[INFO] running `"docker" "rm" "-f" "a8e91fa87f21f5bd4befd965af9aa68baad74575a4cb7bf2299dd207a093b13d"`
[INFO] [stdout] a8e91fa87f21f5bd4befd965af9aa68baad74575a4cb7bf2299dd207a093b13d