[INFO] fetching crate aktoro-channel 0.1.0-alpha.8...
[INFO] checking aktoro-channel-0.1.0-alpha.8 against beta for pr-78714
[INFO] extracting crate aktoro-channel 0.1.0-alpha.8 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate aktoro-channel 0.1.0-alpha.8 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate aktoro-channel 0.1.0-alpha.8
[INFO] finished tweaking crates.io crate aktoro-channel 0.1.0-alpha.8
[INFO] tweaked toml for crates.io crate aktoro-channel 0.1.0-alpha.8 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 53455e2c921f48d2fc61f3414c4ad20c6b76fbc30beb1f708abb136927bda22b
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "53455e2c921f48d2fc61f3414c4ad20c6b76fbc30beb1f708abb136927bda22b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "53455e2c921f48d2fc61f3414c4ad20c6b76fbc30beb1f708abb136927bda22b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "53455e2c921f48d2fc61f3414c4ad20c6b76fbc30beb1f708abb136927bda22b", kill_on_drop: false }`
[INFO] [stdout] 53455e2c921f48d2fc61f3414c4ad20c6b76fbc30beb1f708abb136927bda22b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2a6a8739e7f0350c77604d924338b2ff6f199f292ee98be9cdd0cbd9c6ac941d
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "2a6a8739e7f0350c77604d924338b2ff6f199f292ee98be9cdd0cbd9c6ac941d", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking futures v0.1.30
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]     Checking async-ready v3.0.0
[INFO] [stderr]     Checking async-datagram v3.0.0
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]     Checking net2 v0.2.35
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking smallvec v0.6.13
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking aktoro-channel v0.1.0-alpha.8 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking crossbeam-channel v0.4.4
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.18
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-util-preview-0.3.0-alpha.18/src/lib.rs:4:38
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "async-await", feature(async_await))]
[INFO] [stdout]   |                                      ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking crossbeam v0.7.3
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `futures-util-preview`
[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 `Command { std: "docker" "inspect" "2a6a8739e7f0350c77604d924338b2ff6f199f292ee98be9cdd0cbd9c6ac941d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2a6a8739e7f0350c77604d924338b2ff6f199f292ee98be9cdd0cbd9c6ac941d", kill_on_drop: false }`
[INFO] [stdout] 2a6a8739e7f0350c77604d924338b2ff6f199f292ee98be9cdd0cbd9c6ac941d