[INFO] crate assert_infrequent 0.1.0 is already in cache
[INFO] extracting crate assert_infrequent 0.1.0 into work/ex/beta-1.37-6/sources/1.36.0/reg/assert_infrequent/0.1.0
[INFO] extracting crate assert_infrequent 0.1.0 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/assert_infrequent/0.1.0
[INFO] validating manifest of assert_infrequent-0.1.0 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of assert_infrequent-0.1.0 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing assert_infrequent-0.1.0
[INFO] finished frobbing assert_infrequent-0.1.0
[INFO] frobbed toml for assert_infrequent-0.1.0 written to work/ex/beta-1.37-6/sources/1.36.0/reg/assert_infrequent/0.1.0/Cargo.toml
[INFO] started frobbing assert_infrequent-0.1.0
[INFO] finished frobbing assert_infrequent-0.1.0
[INFO] frobbed toml for assert_infrequent-0.1.0 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/assert_infrequent/0.1.0/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing assert_infrequent-0.1.0 against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-1/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/assert_infrequent/0.1.0:/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-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 7636b33d5cc48b169b2c63f88ba03250e7643408e7086f5d9c540614633d9028
[INFO] running `"docker" "start" "-a" "7636b33d5cc48b169b2c63f88ba03250e7643408e7086f5d9c540614633d9028"`
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling backtrace-sys v0.1.31
[INFO] [stderr]    Compiling backtrace v0.3.34
[INFO] [stderr]    Compiling assert_infrequent v0.1.0 (/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(test)]
[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 `assert_infrequent`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "7636b33d5cc48b169b2c63f88ba03250e7643408e7086f5d9c540614633d9028"`
[INFO] running `"docker" "rm" "-f" "7636b33d5cc48b169b2c63f88ba03250e7643408e7086f5d9c540614633d9028"`
[INFO] [stdout] 7636b33d5cc48b169b2c63f88ba03250e7643408e7086f5d9c540614633d9028