[INFO] updating cached repository cybermatt/fast-luhn
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/cybermatt/fast-luhn
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/cybermatt/fast-luhn" "work/ex/beta-1.38-1/sources/1.37.0/gh/cybermatt/fast-luhn"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/cybermatt/fast-luhn'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/cybermatt/fast-luhn" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cybermatt/fast-luhn"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cybermatt/fast-luhn'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] ead27f1b945aee78cf43663be156466d810d964d
[INFO] sha for GitHub repo cybermatt/fast-luhn: ead27f1b945aee78cf43663be156466d810d964d
[INFO] validating manifest of cybermatt/fast-luhn 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 cybermatt/fast-luhn 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 cybermatt/fast-luhn
[INFO] finished frobbing cybermatt/fast-luhn
[INFO] frobbed toml for cybermatt/fast-luhn written to work/ex/beta-1.38-1/sources/1.37.0/gh/cybermatt/fast-luhn/Cargo.toml
[INFO] started frobbing cybermatt/fast-luhn
[INFO] finished frobbing cybermatt/fast-luhn
[INFO] frobbed toml for cybermatt/fast-luhn written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/cybermatt/fast-luhn/Cargo.toml
[INFO] crate cybermatt/fast-luhn 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 cybermatt/fast-luhn 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-1/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/cybermatt/fast-luhn:/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] b428a8d28a340dbd4aae412f74e7e960f20a6e0b5fcbe10df96a1b77aebff926
[INFO] running `"docker" "start" "-a" "b428a8d28a340dbd4aae412f74e7e960f20a6e0b5fcbe10df96a1b77aebff926"`
[INFO] [stderr]    Compiling syn v0.15.29
[INFO] [stderr]    Compiling proc-macro-hack-impl v0.4.1
[INFO] [stderr]    Compiling spin v0.4.10
[INFO] [stderr]    Compiling pyo3 v0.5.4
[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-0.4.10/src/lib.rs:6:35
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![cfg_attr(feature = "const_fn", feature(const_fn))]
[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 `spin`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "b428a8d28a340dbd4aae412f74e7e960f20a6e0b5fcbe10df96a1b77aebff926"`
[INFO] running `"docker" "rm" "-f" "b428a8d28a340dbd4aae412f74e7e960f20a6e0b5fcbe10df96a1b77aebff926"`
[INFO] [stdout] b428a8d28a340dbd4aae412f74e7e960f20a6e0b5fcbe10df96a1b77aebff926