[INFO] updating cached repository Ragnaroek/mithril
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Ragnaroek/mithril
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Ragnaroek/mithril" "work/ex/beta-1.38-1/sources/1.37.0/gh/Ragnaroek/mithril"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Ragnaroek/mithril'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Ragnaroek/mithril" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Ragnaroek/mithril"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Ragnaroek/mithril'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 87796355568e973033551c4ba2c1d8061af69872
[INFO] sha for GitHub repo Ragnaroek/mithril: 87796355568e973033551c4ba2c1d8061af69872
[INFO] validating manifest of Ragnaroek/mithril 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 Ragnaroek/mithril 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 Ragnaroek/mithril
[INFO] finished frobbing Ragnaroek/mithril
[INFO] frobbed toml for Ragnaroek/mithril written to work/ex/beta-1.38-1/sources/1.37.0/gh/Ragnaroek/mithril/Cargo.toml
[INFO] started frobbing Ragnaroek/mithril
[INFO] finished frobbing Ragnaroek/mithril
[INFO] frobbed toml for Ragnaroek/mithril written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Ragnaroek/mithril/Cargo.toml
[INFO] crate Ragnaroek/mithril 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]     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 Ragnaroek/mithril 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/Ragnaroek/mithril:/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] f813913c5d362d08bc4a137b7795a63e389c8b3a88b32d0292ac6df38af6c90e
[INFO] running `"docker" "start" "-a" "f813913c5d362d08bc4a137b7795a63e389c8b3a88b32d0292ac6df38af6c90e"`
[INFO] [stderr]    Compiling proc-macro2 v0.4.21
[INFO] [stderr]    Compiling rust-ini v0.13.0
[INFO] [stderr]    Compiling serde_test v0.8.23
[INFO] [stderr]    Compiling num_cpus v1.10.0
[INFO] [stderr]    Compiling dirs v1.0.5
[INFO] [stderr]    Compiling skein-ffi v0.5.0
[INFO] [stderr]    Compiling jh-ffi v0.5.0
[INFO] [stderr]    Compiling blake v2.0.0
[INFO] [stderr]    Compiling toml v0.4.8
[INFO] [stderr]    Compiling serde_json v1.0.39
[INFO] [stderr]    Compiling nom v4.1.1
[INFO] [stderr]    Compiling block-buffer v0.7.0
[INFO] [stderr]    Compiling linked-hash-map v0.3.0
[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/skein-ffi-0.5.0/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(rustc_private)]
[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/skein-ffi-0.5.0/src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(libc)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `skein-ffi`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "f813913c5d362d08bc4a137b7795a63e389c8b3a88b32d0292ac6df38af6c90e"`
[INFO] running `"docker" "rm" "-f" "f813913c5d362d08bc4a137b7795a63e389c8b3a88b32d0292ac6df38af6c90e"`
[INFO] [stdout] f813913c5d362d08bc4a137b7795a63e389c8b3a88b32d0292ac6df38af6c90e