[INFO] updating cached repository haetze/server_2_2048
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/haetze/server_2_2048
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/haetze/server_2_2048" "work/ex/beta-1.38-1/sources/1.37.0/gh/haetze/server_2_2048"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/haetze/server_2_2048'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/haetze/server_2_2048" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/haetze/server_2_2048"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/haetze/server_2_2048'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 3d7ce27e5b8871b45b9150cb02d0a9fdd1f92dc5
[INFO] sha for GitHub repo haetze/server_2_2048: 3d7ce27e5b8871b45b9150cb02d0a9fdd1f92dc5
[INFO] validating manifest of haetze/server_2_2048 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 haetze/server_2_2048 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 haetze/server_2_2048
[INFO] finished frobbing haetze/server_2_2048
[INFO] frobbed toml for haetze/server_2_2048 written to work/ex/beta-1.38-1/sources/1.37.0/gh/haetze/server_2_2048/Cargo.toml
[INFO] started frobbing haetze/server_2_2048
[INFO] finished frobbing haetze/server_2_2048
[INFO] frobbed toml for haetze/server_2_2048 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/haetze/server_2_2048/Cargo.toml
[INFO] crate haetze/server_2_2048 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 haetze/server_2_2048 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-1/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/haetze/server_2_2048:/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] e9509fde589559a62012e38040e6811fcf437b2dceef9699a00e160cf5f7a122
[INFO] running `"docker" "start" "-a" "e9509fde589559a62012e38040e6811fcf437b2dceef9699a00e160cf5f7a122"`
[INFO] [stderr]    Compiling bytes v0.4.9
[INFO] [stderr]    Compiling mio v0.6.15
[INFO] [stderr]    Compiling lib_2048 v0.1.0 (https://github.com/haetze/lib_2048?rev=83fdd8e5ab7c0f5e15588cae155e0726dc7ba5d1#83fdd8e5)
[INFO] [stderr]    Compiling tokio-threadpool v0.1.5
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/git/checkouts/lib_2048-cf68a00f66698b73/83fdd8e/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] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "e9509fde589559a62012e38040e6811fcf437b2dceef9699a00e160cf5f7a122"`
[INFO] running `"docker" "rm" "-f" "e9509fde589559a62012e38040e6811fcf437b2dceef9699a00e160cf5f7a122"`
[INFO] [stdout] e9509fde589559a62012e38040e6811fcf437b2dceef9699a00e160cf5f7a122