[INFO] crate kf-protocol 1.1.3 is already in cache
[INFO] testing kf-protocol-1.1.3 against beta-2020-06-03 for beta-1.45-1
[INFO] extracting crate kf-protocol 1.1.3 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate kf-protocol 1.1.3 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 kf-protocol 1.1.3
[INFO] finished tweaking crates.io crate kf-protocol 1.1.3
[INFO] tweaked toml for crates.io crate kf-protocol 1.1.3 written to /workspace/builds/worker-2/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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 1704ae7269ae07accf4751d1c691c87988406774a6335fbb4179fedd2ad8fe45
[INFO] running `"docker" "start" "-a" "1704ae7269ae07accf4751d1c691c87988406774a6335fbb4179fedd2ad8fe45"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling libc v0.2.71
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling nix v0.17.0
[INFO] [stderr]    Compiling async-task v3.0.0
[INFO] [stderr]    Compiling scoped-tls-hkt v0.1.2
[INFO] [stderr]    Compiling tokio v0.2.21
[INFO] [stderr]    Compiling async-trait v0.1.33
[INFO] [stderr]    Compiling futures-util v0.3.5
[INFO] [stderr]    Compiling serde v1.0.111
[INFO] [stderr]    Compiling kv-log-macro v1.0.6
[INFO] [stderr]    Compiling kf-protocol-derive v0.1.0
[INFO] [stderr]    Compiling tokio-util v0.3.1
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling time v0.1.43
[INFO] [stderr]    Compiling socket2 v0.3.12
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling memmap v0.7.0
[INFO] [stderr]    Compiling env_logger v0.7.1
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr]    Compiling chrono v0.4.11
[INFO] [stderr]    Compiling flv-util v0.2.0
[INFO] [stderr]    Compiling flv-util v0.1.1
[INFO] [stderr]    Compiling piper v0.1.3
[INFO] [stderr]    Compiling futures-executor v0.3.5
[INFO] [stderr]    Compiling futures v0.3.5
[INFO] [stderr]    Compiling smol v0.1.11
[INFO] [stderr]    Compiling async-std v1.6.0
[INFO] [stderr]    Compiling kf-protocol-core v0.1.1
[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/kf-protocol-core-0.1.1/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(specialization)]
[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 `kf-protocol-core`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "1704ae7269ae07accf4751d1c691c87988406774a6335fbb4179fedd2ad8fe45"`
[INFO] running `"docker" "rm" "-f" "1704ae7269ae07accf4751d1c691c87988406774a6335fbb4179fedd2ad8fe45"`
[INFO] [stdout] 1704ae7269ae07accf4751d1c691c87988406774a6335fbb4179fedd2ad8fe45