[INFO] updating cached repository someguynamedmatt/kernel
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/someguynamedmatt/kernel
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/someguynamedmatt/kernel" "work/ex/beta-1.38-1/sources/1.37.0/gh/someguynamedmatt/kernel"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/someguynamedmatt/kernel'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/someguynamedmatt/kernel" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/someguynamedmatt/kernel"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/someguynamedmatt/kernel'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 3a317dd6c233b08f256477b4da5abaab325fbfcf
[INFO] sha for GitHub repo someguynamedmatt/kernel: 3a317dd6c233b08f256477b4da5abaab325fbfcf
[INFO] validating manifest of someguynamedmatt/kernel 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 someguynamedmatt/kernel 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 someguynamedmatt/kernel
[INFO] finished frobbing someguynamedmatt/kernel
[INFO] frobbed toml for someguynamedmatt/kernel written to work/ex/beta-1.38-1/sources/1.37.0/gh/someguynamedmatt/kernel/Cargo.toml
[INFO] started frobbing someguynamedmatt/kernel
[INFO] finished frobbing someguynamedmatt/kernel
[INFO] frobbed toml for someguynamedmatt/kernel written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/someguynamedmatt/kernel/Cargo.toml
[INFO] crate someguynamedmatt/kernel 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 someguynamedmatt/kernel 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-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/someguynamedmatt/kernel:/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] ad879eb809ed7e6eba5ed3fbe521cc346156db3736273b9adb22bb2c264581ea
[INFO] running `"docker" "start" "-a" "ad879eb809ed7e6eba5ed3fbe521cc346156db3736273b9adb22bb2c264581ea"`
[INFO] [stderr]    Compiling my_os v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(lang_items)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0522]: definition of an unknown language item: `panic_fmt`
[INFO] [stderr]   --> src/lib.rs:25:1
[INFO] [stderr]    |
[INFO] [stderr] 25 | #[lang = "panic_fmt"] #[no_mangle] pub extern fn panic_fmt() -> !{loop{}}
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`
[INFO] [stderr] 
[INFO] [stderr] error: `#[panic_handler]` function required, but not found
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0522, E0554.
[INFO] [stderr] For more information about an error, try `rustc --explain E0522`.
[INFO] [stderr] error: Could not compile `my_os`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "ad879eb809ed7e6eba5ed3fbe521cc346156db3736273b9adb22bb2c264581ea"`
[INFO] running `"docker" "rm" "-f" "ad879eb809ed7e6eba5ed3fbe521cc346156db3736273b9adb22bb2c264581ea"`
[INFO] [stdout] ad879eb809ed7e6eba5ed3fbe521cc346156db3736273b9adb22bb2c264581ea