[INFO] updating cached repository gyscos/superc4
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/gyscos/superc4
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/gyscos/superc4" "work/ex/beta-1.38-1/sources/1.37.0/gh/gyscos/superc4"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/gyscos/superc4'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/gyscos/superc4" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/gyscos/superc4"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/gyscos/superc4'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] dc5e0cafa7b2b94d33d13a5bb8622d0aa735eb1a
[INFO] sha for GitHub repo gyscos/superc4: dc5e0cafa7b2b94d33d13a5bb8622d0aa735eb1a
[INFO] validating manifest of gyscos/superc4 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 gyscos/superc4 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 gyscos/superc4
[INFO] finished frobbing gyscos/superc4
[INFO] frobbed toml for gyscos/superc4 written to work/ex/beta-1.38-1/sources/1.37.0/gh/gyscos/superc4/Cargo.toml
[INFO] started frobbing gyscos/superc4
[INFO] finished frobbing gyscos/superc4
[INFO] frobbed toml for gyscos/superc4 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/gyscos/superc4/Cargo.toml
[INFO] crate gyscos/superc4 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 gyscos/superc4 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-0/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/gyscos/superc4:/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] 0865f949da0e07caf8f002e15780a6b072a33a6be5fcd524667b75673b6b2965
[INFO] running `"docker" "start" "-a" "0865f949da0e07caf8f002e15780a6b072a33a6be5fcd524667b75673b6b2965"`
[INFO] [stderr]    Compiling superc4 v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(associated_consts)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::iter`
[INFO] [stderr]  --> src/game/game.rs:1:5
[INFO] [stderr]   |
[INFO] [stderr] 1 | use std::iter;
[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 `superc4`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "0865f949da0e07caf8f002e15780a6b072a33a6be5fcd524667b75673b6b2965"`
[INFO] running `"docker" "rm" "-f" "0865f949da0e07caf8f002e15780a6b072a33a6be5fcd524667b75673b6b2965"`
[INFO] [stdout] 0865f949da0e07caf8f002e15780a6b072a33a6be5fcd524667b75673b6b2965