[INFO] crate bitfield-register 0.2.1 is already in cache
[INFO] testing bitfield-register-0.2.1 against beta-2020-06-03 for beta-1.45-1
[INFO] extracting crate bitfield-register 0.2.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate bitfield-register 0.2.1 on toolchain beta-2020-06-03
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate bitfield-register 0.2.1
[INFO] finished tweaking crates.io crate bitfield-register 0.2.1
[INFO] tweaked toml for crates.io crate bitfield-register 0.2.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-06-03" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3f9a31052c89d47b973cdb72ff60ba9bbe353aebfe0b5c3eaabd9b6104ca1cdf
[INFO] running `"docker" "start" "-a" "3f9a31052c89d47b973cdb72ff60ba9bbe353aebfe0b5c3eaabd9b6104ca1cdf"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling bitfield-register-macro v0.2.1
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/bitfield-register-macro-0.2.1/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(proc_macro)]
[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 `bitfield-register-macro`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "3f9a31052c89d47b973cdb72ff60ba9bbe353aebfe0b5c3eaabd9b6104ca1cdf"`
[INFO] running `"docker" "rm" "-f" "3f9a31052c89d47b973cdb72ff60ba9bbe353aebfe0b5c3eaabd9b6104ca1cdf"`
[INFO] [stdout] 3f9a31052c89d47b973cdb72ff60ba9bbe353aebfe0b5c3eaabd9b6104ca1cdf