[INFO] updating cached repository bon-chi/mio_echo_server
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/bon-chi/mio_echo_server
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/bon-chi/mio_echo_server" "work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/mio_echo_server"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/mio_echo_server'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/bon-chi/mio_echo_server" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/mio_echo_server"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/mio_echo_server'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] df24ffad142a840bc696d491bebfac448a92376e
[INFO] sha for GitHub repo bon-chi/mio_echo_server: df24ffad142a840bc696d491bebfac448a92376e
[INFO] validating manifest of bon-chi/mio_echo_server 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 bon-chi/mio_echo_server 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 bon-chi/mio_echo_server
[INFO] finished frobbing bon-chi/mio_echo_server
[INFO] frobbed toml for bon-chi/mio_echo_server written to work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/mio_echo_server/Cargo.toml
[INFO] started frobbing bon-chi/mio_echo_server
[INFO] finished frobbing bon-chi/mio_echo_server
[INFO] frobbed toml for bon-chi/mio_echo_server written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/mio_echo_server/Cargo.toml
[INFO] crate bon-chi/mio_echo_server 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] error: the lock file /mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/mio_echo_server/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing bon-chi/mio_echo_server 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-0/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/mio_echo_server:/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] f1bb754e09b9f8549343acdcc414a11ff8950e8fbed29844a5c2a78b73dc5131
[INFO] running `"docker" "start" "-a" "f1bb754e09b9f8549343acdcc414a11ff8950e8fbed29844a5c2a78b73dc5131"`
[INFO] [stderr]    Compiling mio_echo_server v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0308]: match arms have incompatible types
[INFO] [stderr]    --> src/main.rs:100:18
[INFO] [stderr]     |
[INFO] [stderr] 98  |           let event_set = match self.state {
[INFO] [stderr]     |  _________________________-
[INFO] [stderr] 99  | |             State::Reading(..) => EventSet::readable(),
[INFO] [stderr]     | |                                   -------------------- this is found to be of type `mio::EventSet`
[INFO] [stderr] 100 | |             _ => {}
[INFO] [stderr]     | |                  ^^ expected struct `mio::EventSet`, found ()
[INFO] [stderr] 101 | |         };
[INFO] [stderr]     | |_________- `match` arms have incompatible types
[INFO] [stderr]     |
[INFO] [stderr]     = note: expected type `mio::EventSet`
[INFO] [stderr]                found type `()`
[INFO] [stderr] 
[INFO] [stderr] error[E0308]: mismatched types
[INFO] [stderr]    --> src/main.rs:122:33
[INFO] [stderr]     |
[INFO] [stderr] 122 |     fn unwrap_read_buf(self) -> Vec<u8> {}
[INFO] [stderr]     |        ---------------          ^^^^^^^ expected struct `std::vec::Vec`, found ()
[INFO] [stderr]     |        |
[INFO] [stderr]     |        this function's body doesn't return
[INFO] [stderr]     |
[INFO] [stderr]     = note: expected type `std::vec::Vec<u8>`
[INFO] [stderr]                found type `()`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0308`.
[INFO] [stderr] error: Could not compile `mio_echo_server`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "f1bb754e09b9f8549343acdcc414a11ff8950e8fbed29844a5c2a78b73dc5131"`
[INFO] running `"docker" "rm" "-f" "f1bb754e09b9f8549343acdcc414a11ff8950e8fbed29844a5c2a78b73dc5131"`
[INFO] [stdout] f1bb754e09b9f8549343acdcc414a11ff8950e8fbed29844a5c2a78b73dc5131