[INFO] updating cached repository t-os/kernel
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/t-os/kernel
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/t-os/kernel" "work/ex/beta-1.37-6/sources/1.36.0/gh/t-os/kernel"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/t-os/kernel'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/t-os/kernel" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/t-os/kernel"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/t-os/kernel'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 7ded8100c5ac4ef0a54c888f259cbe7615edf084
[INFO] sha for GitHub repo t-os/kernel: 7ded8100c5ac4ef0a54c888f259cbe7615edf084
[INFO] validating manifest of t-os/kernel 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 t-os/kernel 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 t-os/kernel
[INFO] finished frobbing t-os/kernel
[INFO] frobbed toml for t-os/kernel written to work/ex/beta-1.37-6/sources/1.36.0/gh/t-os/kernel/Cargo.toml
[INFO] started frobbing t-os/kernel
[INFO] finished frobbing t-os/kernel
[INFO] frobbed toml for t-os/kernel written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/t-os/kernel/Cargo.toml
[INFO] crate t-os/kernel 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 t-os/kernel 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-3/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/gh/t-os/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] f9f3768017620137f657978a6afbe60d5641e1807bac0df2ff97b905396608d9
[INFO] running `"docker" "start" "-a" "f9f3768017620137f657978a6afbe60d5641e1807bac0df2ff97b905396608d9"`
[INFO] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] [stderr]    Compiling acpica-sys v0.0.4
[INFO] [stderr]    Compiling bit_field v0.7.0
[INFO] [stderr]    Compiling bitflags v0.4.0
[INFO] [stderr]    Compiling spin v0.4.6
[INFO] [stderr]    Compiling volatile v0.1.0
[INFO] [stderr]    Compiling multiboot2 v0.1.0
[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/spin-0.4.6/src/lib.rs:6:30
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![cfg_attr(feature = "asm", feature(asm))]
[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/spin-0.4.6/src/lib.rs:7:42
[INFO] [stderr]   |
[INFO] [stderr] 7 | #![cfg_attr(feature = "core_intrinsics", feature(core_intrinsics))]
[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/spin-0.4.6/src/lib.rs:8:35
[INFO] [stderr]   |
[INFO] [stderr] 8 | #![cfg_attr(feature = "const_fn", feature(const_fn, const_unsafe_cell_new, const_atomic_usize_new))]
[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 `spin`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "f9f3768017620137f657978a6afbe60d5641e1807bac0df2ff97b905396608d9"`
[INFO] running `"docker" "rm" "-f" "f9f3768017620137f657978a6afbe60d5641e1807bac0df2ff97b905396608d9"`
[INFO] [stdout] f9f3768017620137f657978a6afbe60d5641e1807bac0df2ff97b905396608d9