[INFO] updating cached repository markcol/board100
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/markcol/board100
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/markcol/board100" "work/ex/beta-1.38-1/sources/1.37.0/gh/markcol/board100"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/markcol/board100'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/markcol/board100" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/markcol/board100"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/markcol/board100'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 8034460ad8032ae58f6cffecbac6da698d1e0803
[INFO] sha for GitHub repo markcol/board100: 8034460ad8032ae58f6cffecbac6da698d1e0803
[INFO] validating manifest of markcol/board100 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 markcol/board100 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 markcol/board100
[INFO] finished frobbing markcol/board100
[INFO] frobbed toml for markcol/board100 written to work/ex/beta-1.38-1/sources/1.37.0/gh/markcol/board100/Cargo.toml
[INFO] started frobbing markcol/board100
[INFO] finished frobbing markcol/board100
[INFO] frobbed toml for markcol/board100 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/markcol/board100/Cargo.toml
[INFO] crate markcol/board100 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 markcol/board100 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/markcol/board100:/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] fcb81d15c0d47f637984812f4676ede621ac14b6366ed5e12a0d470db8b66a76
[INFO] running `"docker" "start" "-a" "fcb81d15c0d47f637984812f4676ede621ac14b6366ed5e12a0d470db8b66a76"`
[INFO] [stderr]    Compiling syn v0.15.17
[INFO] [stderr]    Compiling synstructure v0.10.1
[INFO] [stderr]    Compiling failure_derive v0.1.3
[INFO] [stderr]    Compiling failure v0.1.3
[INFO] [stderr]    Compiling square100 v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> src/main.rs:29:1
[INFO] [stderr]    |
[INFO] [stderr] 29 | #![feature(custom_attribute)]
[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 `square100`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "fcb81d15c0d47f637984812f4676ede621ac14b6366ed5e12a0d470db8b66a76"`
[INFO] running `"docker" "rm" "-f" "fcb81d15c0d47f637984812f4676ede621ac14b6366ed5e12a0d470db8b66a76"`
[INFO] [stdout] fcb81d15c0d47f637984812f4676ede621ac14b6366ed5e12a0d470db8b66a76