[INFO] updating cached repository mehcode/advent-of-code-2018
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/mehcode/advent-of-code-2018
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/mehcode/advent-of-code-2018" "work/ex/beta-1.38-1/sources/1.37.0/gh/mehcode/advent-of-code-2018"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/mehcode/advent-of-code-2018'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/mehcode/advent-of-code-2018" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/mehcode/advent-of-code-2018"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/mehcode/advent-of-code-2018'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] e9ce2fb02cf23ee9922d42d7feb3ed9f65682f74
[INFO] sha for GitHub repo mehcode/advent-of-code-2018: e9ce2fb02cf23ee9922d42d7feb3ed9f65682f74
[INFO] validating manifest of mehcode/advent-of-code-2018 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 mehcode/advent-of-code-2018 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 mehcode/advent-of-code-2018
[INFO] finished frobbing mehcode/advent-of-code-2018
[INFO] frobbed toml for mehcode/advent-of-code-2018 written to work/ex/beta-1.38-1/sources/1.37.0/gh/mehcode/advent-of-code-2018/Cargo.toml
[INFO] started frobbing mehcode/advent-of-code-2018
[INFO] finished frobbing mehcode/advent-of-code-2018
[INFO] frobbed toml for mehcode/advent-of-code-2018 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/mehcode/advent-of-code-2018/Cargo.toml
[INFO] crate mehcode/advent-of-code-2018 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 mehcode/advent-of-code-2018 against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/mehcode/advent-of-code-2018:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 532a10c012f1f831ab6011526df0a9d285158a485417e058917e375eaba73bae
[INFO] running `"docker" "start" "-a" "532a10c012f1f831ab6011526df0a9d285158a485417e058917e375eaba73bae"`
[INFO] [stderr]    Compiling advent-of-code-2018 v0.0.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/main.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(type_ascription)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[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 `advent-of-code-2018`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "532a10c012f1f831ab6011526df0a9d285158a485417e058917e375eaba73bae"`
[INFO] running `"docker" "rm" "-f" "532a10c012f1f831ab6011526df0a9d285158a485417e058917e375eaba73bae"`
[INFO] [stdout] 532a10c012f1f831ab6011526df0a9d285158a485417e058917e375eaba73bae