[INFO] crate lb64 0.1.2 is already in cache
[INFO] extracting crate lb64 0.1.2 into work/ex/beta-1.37-6/sources/1.36.0/reg/lb64/0.1.2
[INFO] extracting crate lb64 0.1.2 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/lb64/0.1.2
[INFO] validating manifest of lb64-0.1.2 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 lb64-0.1.2 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 lb64-0.1.2
[INFO] finished frobbing lb64-0.1.2
[INFO] frobbed toml for lb64-0.1.2 written to work/ex/beta-1.37-6/sources/1.36.0/reg/lb64/0.1.2/Cargo.toml
[INFO] started frobbing lb64-0.1.2
[INFO] finished frobbing lb64-0.1.2
[INFO] frobbed toml for lb64-0.1.2 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/lb64/0.1.2/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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[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] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing lb64-0.1.2 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-3/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/lb64/0.1.2:/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] 77f7d592e814a659e7b841aff1fe5ce6b2edd048a9df57d7f303f996949bcf05
[INFO] running `"docker" "start" "-a" "77f7d592e814a659e7b841aff1fe5ce6b2edd048a9df57d7f303f996949bcf05"`
[INFO] [stderr]    Compiling lb64 v0.1.2 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the beta release channel
[INFO] [stderr]   --> src/lib.rs:40:1
[INFO] [stderr]    |
[INFO] [stderr] 40 | #![feature(no_panic_pow)]
[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 `lb64`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "77f7d592e814a659e7b841aff1fe5ce6b2edd048a9df57d7f303f996949bcf05"`
[INFO] running `"docker" "rm" "-f" "77f7d592e814a659e7b841aff1fe5ce6b2edd048a9df57d7f303f996949bcf05"`
[INFO] [stdout] 77f7d592e814a659e7b841aff1fe5ce6b2edd048a9df57d7f303f996949bcf05