[INFO] fetching crate aktoro-channel 0.1.0-alpha.8...
[INFO] extracting crate aktoro-channel 0.1.0-alpha.8 into work/ex/beta-1.37-6/sources/1.36.0/reg/aktoro-channel/0.1.0-alpha.8
[INFO] extracting crate aktoro-channel 0.1.0-alpha.8 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/aktoro-channel/0.1.0-alpha.8
[INFO] validating manifest of aktoro-channel-0.1.0-alpha.8 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of aktoro-channel-0.1.0-alpha.8 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing aktoro-channel-0.1.0-alpha.8
[INFO] finished frobbing aktoro-channel-0.1.0-alpha.8
[INFO] frobbed toml for aktoro-channel-0.1.0-alpha.8 written to work/ex/beta-1.37-6/sources/1.36.0/reg/aktoro-channel/0.1.0-alpha.8/Cargo.toml
[INFO] started frobbing aktoro-channel-0.1.0-alpha.8
[INFO] finished frobbing aktoro-channel-0.1.0-alpha.8
[INFO] frobbed toml for aktoro-channel-0.1.0-alpha.8 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/aktoro-channel/0.1.0-alpha.8/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing aktoro-channel-0.1.0-alpha.8 against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-2/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/aktoro-channel/0.1.0-alpha.8:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 8d8cd5c287e6b353ba0507a62c6c58f79014ca94d19a7646810d50084eec7e3a
[INFO] running `"docker" "start" "-a" "8d8cd5c287e6b353ba0507a62c6c58f79014ca94d19a7646810d50084eec7e3a"`
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling aktoro-channel v0.1.0-alpha.8 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.73s
[INFO] running `"docker" "inspect" "8d8cd5c287e6b353ba0507a62c6c58f79014ca94d19a7646810d50084eec7e3a"`
[INFO] running `"docker" "rm" "-f" "8d8cd5c287e6b353ba0507a62c6c58f79014ca94d19a7646810d50084eec7e3a"`
[INFO] [stdout] 8d8cd5c287e6b353ba0507a62c6c58f79014ca94d19a7646810d50084eec7e3a
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-2/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/aktoro-channel/0.1.0-alpha.8:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-07-23" "test" "--frozen" "--no-run"`
[INFO] [stdout] 30a018aee7adae4ef69e33218649a04eb555c2d1b808647f55eeafef8f8eb266
[INFO] running `"docker" "start" "-a" "30a018aee7adae4ef69e33218649a04eb555c2d1b808647f55eeafef8f8eb266"`
[INFO] [stderr]    Compiling async-ready v3.0.0
[INFO] [stderr]    Compiling async-datagram v3.0.0
[INFO] [stderr]    Compiling async-datagram v2.2.0
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling syn v0.15.42
[INFO] [stderr] error[E0554]: #![feature] may not be used on the beta release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/async-datagram-2.2.0/src/lib.rs:43:1
[INFO] [stderr]    |
[INFO] [stderr] 43 | #![feature(futures_api)]
[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 `async-datagram`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "30a018aee7adae4ef69e33218649a04eb555c2d1b808647f55eeafef8f8eb266"`
[INFO] running `"docker" "rm" "-f" "30a018aee7adae4ef69e33218649a04eb555c2d1b808647f55eeafef8f8eb266"`
[INFO] [stdout] 30a018aee7adae4ef69e33218649a04eb555c2d1b808647f55eeafef8f8eb266