[INFO] updating cached repository https://github.com/adam-mcdaniel/rust-frc
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 5db2e53f7f434442be9bcb6d8a7aa89dbdcf202d
[INFO] testing adam-mcdaniel/rust-frc against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fadam-mcdaniel%2Frust-frc" "work/builds/worker-10/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/adam-mcdaniel/rust-frc on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/adam-mcdaniel/rust-frc
[INFO] finished tweaking git repo https://github.com/adam-mcdaniel/rust-frc
[INFO] tweaked toml for git repo https://github.com/adam-mcdaniel/rust-frc written to work/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/adam-mcdaniel/rust-frc already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-10/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] 17f882d2e3910ef806754b9538deb8aea3777f7cd242f97da6cbc5690c27f2f2
[INFO] running `"docker" "start" "-a" "17f882d2e3910ef806754b9538deb8aea3777f7cd242f97da6cbc5690c27f2f2"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling wpilib-sys v0.3.1
[INFO] [stderr]    Compiling wpilib v0.3.1
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/wpilib-0.3.1/src/lib.rs:8:1
[INFO] [stderr]   |
[INFO] [stderr] 8 | #![feature(concat_idents)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/wpilib-0.3.1/src/lib.rs:9:1
[INFO] [stderr]   |
[INFO] [stderr] 9 | #![feature(self_struct_ctor)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `wpilib`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "17f882d2e3910ef806754b9538deb8aea3777f7cd242f97da6cbc5690c27f2f2"`
[INFO] running `"docker" "rm" "-f" "17f882d2e3910ef806754b9538deb8aea3777f7cd242f97da6cbc5690c27f2f2"`
[INFO] [stdout] 17f882d2e3910ef806754b9538deb8aea3777f7cd242f97da6cbc5690c27f2f2