[INFO] updating cached repository JakubAdamWieczorek/sepultus
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/JakubAdamWieczorek/sepultus
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/JakubAdamWieczorek/sepultus" "work/ex/beta-1.38-1/sources/1.37.0/gh/JakubAdamWieczorek/sepultus"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/JakubAdamWieczorek/sepultus'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/JakubAdamWieczorek/sepultus" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/JakubAdamWieczorek/sepultus"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/JakubAdamWieczorek/sepultus'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] d58aa6579531bde4763561cc701c7822241f4276
[INFO] sha for GitHub repo JakubAdamWieczorek/sepultus: d58aa6579531bde4763561cc701c7822241f4276
[INFO] validating manifest of JakubAdamWieczorek/sepultus 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 JakubAdamWieczorek/sepultus 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 JakubAdamWieczorek/sepultus
[INFO] finished frobbing JakubAdamWieczorek/sepultus
[INFO] frobbed toml for JakubAdamWieczorek/sepultus written to work/ex/beta-1.38-1/sources/1.37.0/gh/JakubAdamWieczorek/sepultus/Cargo.toml
[INFO] started frobbing JakubAdamWieczorek/sepultus
[INFO] finished frobbing JakubAdamWieczorek/sepultus
[INFO] frobbed toml for JakubAdamWieczorek/sepultus written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/JakubAdamWieczorek/sepultus/Cargo.toml
[INFO] crate JakubAdamWieczorek/sepultus 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 JakubAdamWieczorek/sepultus 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-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/JakubAdamWieczorek/sepultus:/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] 31cce3fd6766030e1978d76c7b3d17f425ee558fb8c1e11c183acbbbd57f7bbd
[INFO] running `"docker" "start" "-a" "31cce3fd6766030e1978d76c7b3d17f425ee558fb8c1e11c183acbbbd57f7bbd"`
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling fallible-iterator v0.1.6
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling reduce v0.1.1
[INFO] [stderr]    Compiling num-traits v0.2.7
[INFO] [stderr]    Compiling num-integer v0.1.40
[INFO] [stderr]    Compiling backtrace v0.3.20
[INFO] [stderr]    Compiling num-iter v0.1.38
[INFO] [stderr]    Compiling stringprep v0.1.2
[INFO] [stderr]    Compiling want v0.0.4
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling memchr v1.0.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.1
[INFO] [stderr]    Compiling base64 v0.6.0
[INFO] [stderr]    Compiling gen-stream v0.2.4
[INFO] [stderr]    Compiling backoff v0.1.5
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/gen-stream-0.2.4/src/lib.rs:67:1
[INFO] [stderr]    |
[INFO] [stderr] 67 | #![feature(generator_trait)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/gen-stream-0.2.4/src/lib.rs:68:1
[INFO] [stderr]    |
[INFO] [stderr] 68 | #![feature(gen_future)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/gen-stream-0.2.4/src/lib.rs:69:1
[INFO] [stderr]    |
[INFO] [stderr] 69 | #![feature(never_type)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `gen-stream`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "31cce3fd6766030e1978d76c7b3d17f425ee558fb8c1e11c183acbbbd57f7bbd"`
[INFO] running `"docker" "rm" "-f" "31cce3fd6766030e1978d76c7b3d17f425ee558fb8c1e11c183acbbbd57f7bbd"`
[INFO] [stdout] 31cce3fd6766030e1978d76c7b3d17f425ee558fb8c1e11c183acbbbd57f7bbd