[INFO] updating cached repository feadoor/rustdoku
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/feadoor/rustdoku
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/feadoor/rustdoku" "work/ex/beta-1.37-6/sources/1.36.0/gh/feadoor/rustdoku"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/feadoor/rustdoku'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/feadoor/rustdoku" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/feadoor/rustdoku"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/feadoor/rustdoku'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] aefa643c9e93ba38c4458563983ab6ad7f62af06
[INFO] sha for GitHub repo feadoor/rustdoku: aefa643c9e93ba38c4458563983ab6ad7f62af06
[INFO] validating manifest of feadoor/rustdoku 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 feadoor/rustdoku 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 feadoor/rustdoku
[INFO] finished frobbing feadoor/rustdoku
[INFO] frobbed toml for feadoor/rustdoku written to work/ex/beta-1.37-6/sources/1.36.0/gh/feadoor/rustdoku/Cargo.toml
[INFO] started frobbing feadoor/rustdoku
[INFO] finished frobbing feadoor/rustdoku
[INFO] frobbed toml for feadoor/rustdoku written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/feadoor/rustdoku/Cargo.toml
[INFO] crate feadoor/rustdoku 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] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing feadoor/rustdoku 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-1/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/gh/feadoor/rustdoku:/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] e0fcd58b2f88abc0ad4829885d363ffe33ba38ae1edf5b33edd1dca05dc71943
[INFO] running `"docker" "start" "-a" "e0fcd58b2f88abc0ad4829885d363ffe33ba38ae1edf5b33edd1dca05dc71943"`
[INFO] [stderr]    Compiling either v1.0.2
[INFO] [stderr]    Compiling itertools v0.5.7
[INFO] [stderr]    Compiling rustdoku 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(generators, generator_trait)]
[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 `rustdoku`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "e0fcd58b2f88abc0ad4829885d363ffe33ba38ae1edf5b33edd1dca05dc71943"`
[INFO] running `"docker" "rm" "-f" "e0fcd58b2f88abc0ad4829885d363ffe33ba38ae1edf5b33edd1dca05dc71943"`
[INFO] [stdout] e0fcd58b2f88abc0ad4829885d363ffe33ba38ae1edf5b33edd1dca05dc71943