[INFO] crate backoff-futures 0.1.1 is already in cache
[INFO] testing backoff-futures-0.1.1 against beta-2019-09-28 for beta-1.39-1
[INFO] extracting crate backoff-futures 0.1.1 into work/builds/worker-1/source
[INFO] validating manifest of crates.io crate backoff-futures 0.1.1 on toolchain beta-2019-09-28
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate backoff-futures 0.1.1
[INFO] finished tweaking crates.io crate backoff-futures 0.1.1
[INFO] tweaked toml for crates.io crate backoff-futures 0.1.1 written to work/builds/worker-1/source/Cargo.toml
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-1/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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-2019-09-28" "build" "--frozen"`
[INFO] [stdout] 622f06b5adb27533ae9b110b2aa0f3bd73cbe823361c403a470a56038a308c98
[INFO] running `"docker" "start" "-a" "622f06b5adb27533ae9b110b2aa0f3bd73cbe823361c403a470a56038a308c98"`
[INFO] [stderr]    Compiling backoff v0.1.5
[INFO] [stderr]    Compiling backoff-futures v0.1.1 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.46s
[INFO] running `"docker" "inspect" "622f06b5adb27533ae9b110b2aa0f3bd73cbe823361c403a470a56038a308c98"`
[INFO] running `"docker" "rm" "-f" "622f06b5adb27533ae9b110b2aa0f3bd73cbe823361c403a470a56038a308c98"`
[INFO] [stdout] 622f06b5adb27533ae9b110b2aa0f3bd73cbe823361c403a470a56038a308c98
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-1/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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-2019-09-28" "test" "--frozen" "--no-run"`
[INFO] [stdout] 09b1e6476834698d81083638424c720fe84ea29b68b1e5b59a0f50334a3aaf11
[INFO] running `"docker" "start" "-a" "09b1e6476834698d81083638424c720fe84ea29b68b1e5b59a0f50334a3aaf11"`
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling curl v0.4.25
[INFO] [stderr]    Compiling isahc v0.6.0
[INFO] [stderr]    Compiling curl-sys v0.4.23
[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 futures-util-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling sluice v0.4.1
[INFO] [stderr]    Compiling futures-executor-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling futures-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling backoff-futures v0.1.1 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]   --> src/lib.rs:52:19
[INFO] [stderr]    |
[INFO] [stderr] 52 | #![cfg_attr(test, 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 `backoff-futures`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "09b1e6476834698d81083638424c720fe84ea29b68b1e5b59a0f50334a3aaf11"`
[INFO] running `"docker" "rm" "-f" "09b1e6476834698d81083638424c720fe84ea29b68b1e5b59a0f50334a3aaf11"`
[INFO] [stdout] 09b1e6476834698d81083638424c720fe84ea29b68b1e5b59a0f50334a3aaf11