[INFO] updating cached repository yuu/rust-future-example
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/yuu/rust-future-example
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/yuu/rust-future-example" "work/ex/beta-1.38-1/sources/1.37.0/gh/yuu/rust-future-example"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/yuu/rust-future-example'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/yuu/rust-future-example" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yuu/rust-future-example"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yuu/rust-future-example'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c5704fd681f1180c6d45ceaf720eccd7d1e0247b
[INFO] sha for GitHub repo yuu/rust-future-example: c5704fd681f1180c6d45ceaf720eccd7d1e0247b
[INFO] validating manifest of yuu/rust-future-example on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of yuu/rust-future-example on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing yuu/rust-future-example
[INFO] finished frobbing yuu/rust-future-example
[INFO] frobbed toml for yuu/rust-future-example written to work/ex/beta-1.38-1/sources/1.37.0/gh/yuu/rust-future-example/Cargo.toml
[INFO] started frobbing yuu/rust-future-example
[INFO] finished frobbing yuu/rust-future-example
[INFO] frobbed toml for yuu/rust-future-example written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yuu/rust-future-example/Cargo.toml
[INFO] crate yuu/rust-future-example already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing yuu/rust-future-example against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/yuu/rust-future-example:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 386872f212b5f6f50677163950c0bf0a9b131d951bf3426a87a186dd7ea5a067
[INFO] running `"docker" "start" "-a" "386872f212b5f6f50677163950c0bf0a9b131d951bf3426a87a186dd7ea5a067"`
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling log v0.4.7
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling async-util v0.1.0 (https://github.com/tokio-rs/async#e1b3ba3d)
[INFO] [stderr]    Compiling syn v0.15.40
[INFO] [stderr]    Compiling arc-waker v0.1.0 (https://github.com/tokio-rs/async#e1b3ba3d)
[INFO] [stderr]    Compiling crossbeam-utils v0.6.5
[INFO] [stderr]    Compiling crossbeam-utils v0.6.5 (https://github.com/stjepang/crossbeam?branch=raw-parker#e2a7760f)
[INFO] [stderr]    Compiling tracing-core v0.1.2
[INFO] [stderr]    Compiling parking_lot_core v0.6.1
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling tokio-sync v0.2.0 (https://github.com/tokio-rs/tokio#e88d10a3)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/git/checkouts/tokio-377c595163f99a10/e88d10a/tokio-sync/src/lib.rs:10:1
[INFO] [stderr]    |
[INFO] [stderr] 10 | #![feature(async_await)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]    Compiling tokio-executor v0.2.0 (https://github.com/tokio-rs/tokio#e88d10a3)
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.1
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling crossbeam-channel v0.3.8
[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 `tokio-sync`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "386872f212b5f6f50677163950c0bf0a9b131d951bf3426a87a186dd7ea5a067"`
[INFO] running `"docker" "rm" "-f" "386872f212b5f6f50677163950c0bf0a9b131d951bf3426a87a186dd7ea5a067"`
[INFO] [stdout] 386872f212b5f6f50677163950c0bf0a9b131d951bf3426a87a186dd7ea5a067