[INFO] updating cached repository jkcclemens/fswatch
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/jkcclemens/fswatch
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/jkcclemens/fswatch" "work/ex/beta-1.38-1/sources/1.37.0/gh/jkcclemens/fswatch"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/jkcclemens/fswatch'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/jkcclemens/fswatch" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/jkcclemens/fswatch"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/jkcclemens/fswatch'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 82bcf5aed846c070b0edf4ce679a28c537786662
[INFO] sha for GitHub repo jkcclemens/fswatch: 82bcf5aed846c070b0edf4ce679a28c537786662
[INFO] validating manifest of jkcclemens/fswatch 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 jkcclemens/fswatch 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 jkcclemens/fswatch
[INFO] finished frobbing jkcclemens/fswatch
[INFO] frobbed toml for jkcclemens/fswatch written to work/ex/beta-1.38-1/sources/1.37.0/gh/jkcclemens/fswatch/Cargo.toml
[INFO] started frobbing jkcclemens/fswatch
[INFO] finished frobbing jkcclemens/fswatch
[INFO] frobbed toml for jkcclemens/fswatch written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/jkcclemens/fswatch/Cargo.toml
[INFO] crate jkcclemens/fswatch 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 jkcclemens/fswatch 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-4/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/jkcclemens/fswatch:/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] fdf9de8a841d88d5ae9fbc63e5b1ef9210df8003bfc30ded44d24e21f4c88579
[INFO] running `"docker" "start" "-a" "fdf9de8a841d88d5ae9fbc63e5b1ef9210df8003bfc30ded44d24e21f4c88579"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling fswatch-sys v0.1.10
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/fswatch-sys-0.1.10/src/lib.rs:6:1
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![feature(const_fn)]
[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 `fswatch-sys`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "fdf9de8a841d88d5ae9fbc63e5b1ef9210df8003bfc30ded44d24e21f4c88579"`
[INFO] running `"docker" "rm" "-f" "fdf9de8a841d88d5ae9fbc63e5b1ef9210df8003bfc30ded44d24e21f4c88579"`
[INFO] [stdout] fdf9de8a841d88d5ae9fbc63e5b1ef9210df8003bfc30ded44d24e21f4c88579