[INFO] updating cached repository awelkie/example_scheduler
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/awelkie/example_scheduler
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/awelkie/example_scheduler" "work/ex/beta-1.37-6/sources/1.36.0/gh/awelkie/example_scheduler"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/awelkie/example_scheduler'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/awelkie/example_scheduler" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/awelkie/example_scheduler"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/awelkie/example_scheduler'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 1ff1b62f573f86eb27b905fd90f5eb9aa8392797
[INFO] sha for GitHub repo awelkie/example_scheduler: 1ff1b62f573f86eb27b905fd90f5eb9aa8392797
[INFO] validating manifest of awelkie/example_scheduler 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 awelkie/example_scheduler 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 awelkie/example_scheduler
[INFO] finished frobbing awelkie/example_scheduler
[INFO] frobbed toml for awelkie/example_scheduler written to work/ex/beta-1.37-6/sources/1.36.0/gh/awelkie/example_scheduler/Cargo.toml
[INFO] started frobbing awelkie/example_scheduler
[INFO] finished frobbing awelkie/example_scheduler
[INFO] frobbed toml for awelkie/example_scheduler written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/awelkie/example_scheduler/Cargo.toml
[INFO] crate awelkie/example_scheduler 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 awelkie/example_scheduler 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-0/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/awelkie/example_scheduler:/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] 5f7b544079ac42c89707101e39033124e0d6806d265bb9980c3dcc46e770ada3
[INFO] running `"docker" "start" "-a" "5f7b544079ac42c89707101e39033124e0d6806d265bb9980c3dcc46e770ada3"`
[INFO] [stderr]    Compiling volatile-register v0.1.2
[INFO] [stderr]    Compiling cortex-m v0.1.4
[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/cortex-m-0.1.4/src/lib.rs:14:1
[INFO] [stderr]    |
[INFO] [stderr] 14 | #![feature(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 `cortex-m`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "5f7b544079ac42c89707101e39033124e0d6806d265bb9980c3dcc46e770ada3"`
[INFO] running `"docker" "rm" "-f" "5f7b544079ac42c89707101e39033124e0d6806d265bb9980c3dcc46e770ada3"`
[INFO] [stdout] 5f7b544079ac42c89707101e39033124e0d6806d265bb9980c3dcc46e770ada3