[INFO] updating cached repository https://github.com/haetze/server_2048
[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] ab209f96a4baa28b200d5a2a3f0ef04ac666cf06
[INFO] testing haetze/server_2048 against beta-2019-09-28 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhaetze%2Fserver_2048" "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/haetze/server_2048 on toolchain beta-2019-09-28
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/haetze/server_2048
[INFO] finished tweaking git repo https://github.com/haetze/server_2048
[INFO] tweaked toml for git repo https://github.com/haetze/server_2048 written to work/builds/worker-5/source/Cargo.toml
[INFO] crate git repo https://github.com/haetze/server_2048 already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: the lock file /big/crater/work/builds/worker-5/source/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Updating git repository `https://github.com/haetze/lib_2048`
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "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" "+beta-2019-09-28" "build" "--frozen"`
[INFO] [stdout] 5f5b7f0811880f6ed0a56405a3e4b48b06db709b13906ace6b3cc0548a51b49f
[INFO] running `"docker" "start" "-a" "5f5b7f0811880f6ed0a56405a3e4b48b06db709b13906ace6b3cc0548a51b49f"`
[INFO] [stderr]    Compiling lib_2048 v0.1.0 (https://github.com/haetze/lib_2048?rev=a3c1424f3f50847bb63a5fb5c79f9d3ced91d821#a3c1424f)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/git/checkouts/lib_2048-cf68a00f66698b73/a3c1424/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(extern_prelude)]
[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 `lib_2048`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "5f5b7f0811880f6ed0a56405a3e4b48b06db709b13906ace6b3cc0548a51b49f"`
[INFO] running `"docker" "rm" "-f" "5f5b7f0811880f6ed0a56405a3e4b48b06db709b13906ace6b3cc0548a51b49f"`
[INFO] [stdout] 5f5b7f0811880f6ed0a56405a3e4b48b06db709b13906ace6b3cc0548a51b49f