[INFO] updating cached repository https://github.com/kjellkongsvik/ar
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/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] d680cadb2e34935ce1f29b1ce64ff9bcebd4250f
[INFO] testing kjellkongsvik/ar against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkjellkongsvik%2Far" "work/builds/worker-5/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-5/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kjellkongsvik/ar on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/kjellkongsvik/ar
[INFO] finished tweaking git repo https://github.com/kjellkongsvik/ar
[INFO] tweaked toml for git repo https://github.com/kjellkongsvik/ar written to work/builds/worker-5/source/Cargo.toml
[INFO] crate git repo https://github.com/kjellkongsvik/ar already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-5/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" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] 910e92007fb75e950d19dce36832d11c901e9722407b8728c867f8d56f680ebe
[INFO] running `"docker" "start" "-a" "910e92007fb75e950d19dce36832d11c901e9722407b8728c867f8d56f680ebe"`
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-executor-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling ar v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0658]: async fn is unstable
[INFO] [stderr]   --> src/main.rs:5:1
[INFO] [stderr]    |
[INFO] [stderr] 5  | / async fn print_hello(tx: Sender<i32>) {
[INFO] [stderr] 6  | |     let numbers = &[2, 5, 6, 7, 8];
[INFO] [stderr] 7  | |     for n in numbers {
[INFO] [stderr] 8  | |         tx.send(*n).unwrap();
[INFO] [stderr] 9  | |     }
[INFO] [stderr] 10 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: for more information, see https://github.com/rust-lang/rust/issues/50547
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: async fn is unstable
[INFO] [stderr]   --> src/main.rs:12:1
[INFO] [stderr]    |
[INFO] [stderr] 12 | / async fn print_world(rx: Receiver<i32>) {
[INFO] [stderr] 13 | |     for i in rx.iter() {
[INFO] [stderr] 14 | |         println!("{}", i);
[INFO] [stderr] 15 | |     }
[INFO] [stderr] 16 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: for more information, see https://github.com/rust-lang/rust/issues/50547
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: async fn is unstable
[INFO] [stderr]   --> src/main.rs:18:1
[INFO] [stderr]    |
[INFO] [stderr] 18 | / async fn async_main() {
[INFO] [stderr] 19 | |     let (tx, rx): (Sender<i32>, Receiver<i32>) = channel();
[INFO] [stderr] 20 | |     let f = print_hello(tx);
[INFO] [stderr] 21 | |     let g = print_world(rx);
[INFO] [stderr] 22 | |
[INFO] [stderr] 23 | |     (f.await, g.await);
[INFO] [stderr] 24 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: for more information, see https://github.com/rust-lang/rust/issues/50547
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: async/await is unstable
[INFO] [stderr]   --> src/main.rs:23:6
[INFO] [stderr]    |
[INFO] [stderr] 23 |     (f.await, g.await);
[INFO] [stderr]    |      ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: for more information, see https://github.com/rust-lang/rust/issues/50547
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: async/await is unstable
[INFO] [stderr]   --> src/main.rs:23:15
[INFO] [stderr]    |
[INFO] [stderr] 23 |     (f.await, g.await);
[INFO] [stderr]    |               ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: for more information, see https://github.com/rust-lang/rust/issues/50547
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 5 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0658`.
[INFO] [stderr] error: Could not compile `ar`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "910e92007fb75e950d19dce36832d11c901e9722407b8728c867f8d56f680ebe"`
[INFO] running `"docker" "rm" "-f" "910e92007fb75e950d19dce36832d11c901e9722407b8728c867f8d56f680ebe"`
[INFO] [stdout] 910e92007fb75e950d19dce36832d11c901e9722407b8728c867f8d56f680ebe