[INFO] updating cached repository alhaad/vshnu-os
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/alhaad/vshnu-os
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/alhaad/vshnu-os" "work/ex/beta-1.37-6/sources/1.36.0/gh/alhaad/vshnu-os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/alhaad/vshnu-os'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/alhaad/vshnu-os" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/alhaad/vshnu-os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/alhaad/vshnu-os'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] e4439f972a4dc8bc8d74622fc6af1554c3403f0a
[INFO] sha for GitHub repo alhaad/vshnu-os: e4439f972a4dc8bc8d74622fc6af1554c3403f0a
[INFO] validating manifest of alhaad/vshnu-os 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 alhaad/vshnu-os 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 alhaad/vshnu-os
[INFO] finished frobbing alhaad/vshnu-os
[INFO] frobbed toml for alhaad/vshnu-os written to work/ex/beta-1.37-6/sources/1.36.0/gh/alhaad/vshnu-os/Cargo.toml
[INFO] started frobbing alhaad/vshnu-os
[INFO] finished frobbing alhaad/vshnu-os
[INFO] frobbed toml for alhaad/vshnu-os written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/alhaad/vshnu-os/Cargo.toml
[INFO] crate alhaad/vshnu-os 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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing alhaad/vshnu-os against 1.36.0 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-2/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/gh/alhaad/vshnu-os:/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] c2b8881ac8c5fa26b412f8f3ef196f2386f00a11e03c099685b108162f351af3
[INFO] running `"docker" "start" "-a" "c2b8881ac8c5fa26b412f8f3ef196f2386f00a11e03c099685b108162f351af3"`
[INFO] [stderr]    Compiling compiler_builtins v0.1.0 (https://github.com/rust-lang-nursery/compiler-builtins#67e0908d)
[INFO] [stderr]    Compiling rlibc v1.0.0
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/git/checkouts/compiler-builtins-ec094dc45a0179c8/67e0908/build.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(i128_type)]
[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 `compiler_builtins`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "c2b8881ac8c5fa26b412f8f3ef196f2386f00a11e03c099685b108162f351af3"`
[INFO] running `"docker" "rm" "-f" "c2b8881ac8c5fa26b412f8f3ef196f2386f00a11e03c099685b108162f351af3"`
[INFO] [stdout] c2b8881ac8c5fa26b412f8f3ef196f2386f00a11e03c099685b108162f351af3