[INFO] updating cached repository system76/dbg2
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/system76/dbg2
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/system76/dbg2" "work/ex/beta-1.38-1/sources/1.37.0/gh/system76/dbg2"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/system76/dbg2'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/system76/dbg2" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/system76/dbg2"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/system76/dbg2'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 5feec2677c03618a309ea54250263a87bf33957d
[INFO] sha for GitHub repo system76/dbg2: 5feec2677c03618a309ea54250263a87bf33957d
[INFO] validating manifest of system76/dbg2 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 system76/dbg2 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 system76/dbg2
[INFO] finished frobbing system76/dbg2
[INFO] frobbed toml for system76/dbg2 written to work/ex/beta-1.38-1/sources/1.37.0/gh/system76/dbg2/Cargo.toml
[INFO] started frobbing system76/dbg2
[INFO] finished frobbing system76/dbg2
[INFO] frobbed toml for system76/dbg2 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/system76/dbg2/Cargo.toml
[INFO] crate system76/dbg2 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 system76/dbg2 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-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/system76/dbg2:/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] 3fa9544a7ea492d86c2cb280bc23501b48f8e3f0ac070f051946c45d18dd441e
[INFO] running `"docker" "start" "-a" "3fa9544a7ea492d86c2cb280bc23501b48f8e3f0ac070f051946c45d18dd441e"`
[INFO] [stderr]    Compiling redox_hwio 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/redox_hwio-0.1.0/src/lib.rs:2:63
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![cfg_attr(any(target_arch = "x86", target_arch = "x86_64"), 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/redox_hwio-0.1.0/src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(const_fn)]
[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/redox_hwio-0.1.0/src/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![feature(core_intrinsics)]
[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 `redox_hwio`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "3fa9544a7ea492d86c2cb280bc23501b48f8e3f0ac070f051946c45d18dd441e"`
[INFO] running `"docker" "rm" "-f" "3fa9544a7ea492d86c2cb280bc23501b48f8e3f0ac070f051946c45d18dd441e"`
[INFO] [stdout] 3fa9544a7ea492d86c2cb280bc23501b48f8e3f0ac070f051946c45d18dd441e