[INFO] updating cached repository https://github.com/gyng/midcat
[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] 77677cdabbb18277e6046fc1450d49895c30c61e
[INFO] testing gyng/midcat against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgyng%2Fmidcat" "work/builds/worker-7/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/gyng/midcat 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/gyng/midcat
[INFO] finished tweaking git repo https://github.com/gyng/midcat
[INFO] tweaked toml for git repo https://github.com/gyng/midcat written to work/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/gyng/midcat 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-7/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-7/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] c8c9764c23382e246bd2c226d2620bccb322e79310577e98ba03b8c584312fe7
[INFO] running `"docker" "start" "-a" "c8c9764c23382e246bd2c226d2620bccb322e79310577e98ba03b8c584312fe7"`
[INFO] [stderr]    Compiling num-bigint v0.2.1
[INFO] [stderr]    Compiling rand v0.5.5
[INFO] [stderr]    Compiling alsa-sys v0.1.1
[INFO] [stderr]    Compiling regex v0.2.2
[INFO] [stderr]    Compiling cpal v0.4.5
[INFO] [stderr]    Compiling docopt v0.8.1
[INFO] [stderr]    Compiling num-rational v0.2.1
[INFO] [stderr]    Compiling num v0.2.0
[INFO] [stderr]    Compiling synthrs v0.1.0 (https://github.com/gyng/synthrs?rev=a067f2bee46e5f8593003dc4ad5b6df97bdb3898#a067f2be)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/git/checkouts/synthrs-a4b8c03c849616c3/a067f2b/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(fn_traits, unboxed_closures)]
[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 `synthrs`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "c8c9764c23382e246bd2c226d2620bccb322e79310577e98ba03b8c584312fe7"`
[INFO] running `"docker" "rm" "-f" "c8c9764c23382e246bd2c226d2620bccb322e79310577e98ba03b8c584312fe7"`
[INFO] [stdout] c8c9764c23382e246bd2c226d2620bccb322e79310577e98ba03b8c584312fe7