[INFO] updating cached repository https://github.com/rrichardson/tokio-cookbook
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 989e8f4bef9e4d670237ffeab578afee160d42ae
[INFO] testing rrichardson/tokio-cookbook against 1.44.0 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frrichardson%2Ftokio-cookbook" "/workspace/builds/worker-8/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/rrichardson/tokio-cookbook on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/rrichardson/tokio-cookbook
[INFO] finished tweaking git repo https://github.com/rrichardson/tokio-cookbook
[INFO] tweaked toml for git repo https://github.com/rrichardson/tokio-cookbook written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/rrichardson/tokio-cookbook already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "+1.44.0" "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] 290619726c357b6de799c540df83e083afc922bb0cd4afe55d56c6876d203dc7
[INFO] running `"docker" "start" "-a" "290619726c357b6de799c540df83e083afc922bb0cd4afe55d56c6876d203dc7"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling spin v0.5.2
[INFO] [stderr]    Compiling proc-macro2 v1.0.3
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling getrandom v0.1.12
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling ppv-lite86 v0.2.5
[INFO] [stderr]    Compiling proc-macro-nested v0.1.3
[INFO] [stderr]    Compiling pin-utils v0.1.0-alpha.4
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling scopeguard v1.0.0
[INFO] [stderr]    Compiling arrayvec v0.4.11
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]    Compiling lock_api v0.3.1
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling iovec v0.1.2
[INFO] [stderr]    Compiling num_cpus v1.10.1
[INFO] [stderr]    Compiling net2 v0.2.33
[INFO] [stderr]    Compiling memoffset v0.5.1
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling tracing-core v0.1.6
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling mio v0.6.19
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[INFO] [stderr]    Compiling c2-chacha v0.2.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.2
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling crossbeam-deque v0.7.1
[INFO] [stderr]    Compiling rand v0.7.1
[INFO] [stderr]    Compiling tokio-io v0.2.0-alpha.4
[INFO] [stderr]    Compiling mio-uds v0.6.7
[INFO] [stderr]    Compiling tokio-codec v0.2.0-alpha.4
[INFO] [stderr]    Compiling proc-macro-hack v0.5.9
[INFO] [stderr]    Compiling tracing-attributes v0.1.3
[INFO] [stderr]    Compiling tokio-macros v0.2.0-alpha.4
[INFO] [stderr]    Compiling futures-join-macro-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling tracing v0.1.9
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.18
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-util-preview-0.3.0-alpha.18/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" "290619726c357b6de799c540df83e083afc922bb0cd4afe55d56c6876d203dc7"`
[INFO] running `"docker" "rm" "-f" "290619726c357b6de799c540df83e083afc922bb0cd4afe55d56c6876d203dc7"`
[INFO] [stdout] 290619726c357b6de799c540df83e083afc922bb0cd4afe55d56c6876d203dc7