[INFO] updating cached repository andysalerno/rust_async_example
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/andysalerno/rust_async_example
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/andysalerno/rust_async_example" "work/ex/beta-1.38-1/sources/1.37.0/gh/andysalerno/rust_async_example"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/andysalerno/rust_async_example'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/andysalerno/rust_async_example" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/andysalerno/rust_async_example"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/andysalerno/rust_async_example'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 8ccf54bf7b42f342156c58c0746eba86d8ce15fc
[INFO] sha for GitHub repo andysalerno/rust_async_example: 8ccf54bf7b42f342156c58c0746eba86d8ce15fc
[INFO] validating manifest of andysalerno/rust_async_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 andysalerno/rust_async_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 andysalerno/rust_async_example
[INFO] finished frobbing andysalerno/rust_async_example
[INFO] frobbed toml for andysalerno/rust_async_example written to work/ex/beta-1.38-1/sources/1.37.0/gh/andysalerno/rust_async_example/Cargo.toml
[INFO] started frobbing andysalerno/rust_async_example
[INFO] finished frobbing andysalerno/rust_async_example
[INFO] frobbed toml for andysalerno/rust_async_example written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/andysalerno/rust_async_example/Cargo.toml
[INFO] crate andysalerno/rust_async_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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing andysalerno/rust_async_example against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/andysalerno/rust_async_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" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] a4761bdf70e988f0597b18bcc3436bbd2d8aa58c703daf6d581912dfc2a99104
[INFO] running `"docker" "start" "-a" "a4761bdf70e988f0597b18bcc3436bbd2d8aa58c703daf6d581912dfc2a99104"`
[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 syn v0.15.40
[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 crossbeam-channel v0.3.8
[INFO] [stderr]    Compiling crossbeam-deque v0.6.3
[INFO] [stderr]    Compiling mio-uds v0.6.7
[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" "a4761bdf70e988f0597b18bcc3436bbd2d8aa58c703daf6d581912dfc2a99104"`
[INFO] running `"docker" "rm" "-f" "a4761bdf70e988f0597b18bcc3436bbd2d8aa58c703daf6d581912dfc2a99104"`
[INFO] [stdout] a4761bdf70e988f0597b18bcc3436bbd2d8aa58c703daf6d581912dfc2a99104