[INFO] crate juliex 0.3.0-alpha.8 is already in cache
[INFO] testing juliex-0.3.0-alpha.8 against beta-2020-06-03 for beta-1.45-1
[INFO] extracting crate juliex 0.3.0-alpha.8 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate juliex 0.3.0-alpha.8 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 juliex 0.3.0-alpha.8
[INFO] finished tweaking crates.io crate juliex 0.3.0-alpha.8
[INFO] tweaked toml for crates.io crate juliex 0.3.0-alpha.8 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate crates.io crate juliex 0.3.0-alpha.8 already has a lockfile, it will not be regenerated
[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-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] eb598610c6c7060866c3b988de092fc21f8732a5daa466d89ef86e56bead383a
[INFO] running `"docker" "start" "-a" "eb598610c6c7060866c3b988de092fc21f8732a5daa466d89ef86e56bead383a"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling lazy_static v1.2.0
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling cfg-if v0.1.6
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling arrayvec v0.4.10
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling nodrop v0.1.13
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling c2-chacha v0.2.2
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.2
[INFO] [stderr]    Compiling getrandom v0.1.3
[INFO] [stderr]    Compiling num_cpus v1.10.0
[INFO] [stderr]    Compiling crossbeam-deque v0.7.1
[INFO] [stderr]    Compiling rand_core v0.5.0
[INFO] [stderr]    Compiling crossbeam v0.7.2
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling rand v0.7.0
[INFO] [stderr]    Compiling proc-macro-hack v0.5.7
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.17
[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/futures-util-preview-0.3.0-alpha.17/src/lib.rs:4:38
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![cfg_attr(feature = "async-await", feature(async_await))]
[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 `futures-util-preview`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "eb598610c6c7060866c3b988de092fc21f8732a5daa466d89ef86e56bead383a"`
[INFO] running `"docker" "rm" "-f" "eb598610c6c7060866c3b988de092fc21f8732a5daa466d89ef86e56bead383a"`
[INFO] [stdout] eb598610c6c7060866c3b988de092fc21f8732a5daa466d89ef86e56bead383a