[INFO] updating cached repository MercuryProject/mercury
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/MercuryProject/mercury
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/MercuryProject/mercury" "work/ex/beta-1.37-6/sources/1.36.0/gh/MercuryProject/mercury"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/MercuryProject/mercury'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/MercuryProject/mercury" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/MercuryProject/mercury"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/MercuryProject/mercury'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c888682b76c2b9c16c00b5c9f43d411f8f47a3ad
[INFO] sha for GitHub repo MercuryProject/mercury: c888682b76c2b9c16c00b5c9f43d411f8f47a3ad
[INFO] validating manifest of MercuryProject/mercury on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of MercuryProject/mercury on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing MercuryProject/mercury
[INFO] finished frobbing MercuryProject/mercury
[INFO] frobbed toml for MercuryProject/mercury written to work/ex/beta-1.37-6/sources/1.36.0/gh/MercuryProject/mercury/Cargo.toml
[INFO] started frobbing MercuryProject/mercury
[INFO] finished frobbing MercuryProject/mercury
[INFO] frobbed toml for MercuryProject/mercury written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/MercuryProject/mercury/Cargo.toml
[INFO] crate MercuryProject/mercury already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: the lock file /mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/gh/MercuryProject/mercury/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing MercuryProject/mercury against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/MercuryProject/mercury:/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" "+beta-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 8c588dc6fcd936cd1b87d2e2ad54b38b279c89c8b25ebd96e5e00c01dbe4f652
[INFO] running `"docker" "start" "-a" "8c588dc6fcd936cd1b87d2e2ad54b38b279c89c8b25ebd96e5e00c01dbe4f652"`
[INFO] [stderr]    Compiling spin v0.3.5
[INFO] [stderr]    Compiling rlibc v0.1.5
[INFO] [stderr] error[E0554]: #![feature] may not be used on the beta release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/spin-0.3.5/src/lib.rs:6:1
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![feature(const_fn, asm)]
[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 `spin`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "8c588dc6fcd936cd1b87d2e2ad54b38b279c89c8b25ebd96e5e00c01dbe4f652"`
[INFO] running `"docker" "rm" "-f" "8c588dc6fcd936cd1b87d2e2ad54b38b279c89c8b25ebd96e5e00c01dbe4f652"`
[INFO] [stdout] 8c588dc6fcd936cd1b87d2e2ad54b38b279c89c8b25ebd96e5e00c01dbe4f652