[INFO] cloning repository https://github.com/psFried/roman-numerals-rust
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/psFried/roman-numerals-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpsFried%2Froman-numerals-rust"`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpsFried%2Froman-numerals-rust'...
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] a5eb19ba0468ee970bf2118998631a74df84ab43
[INFO] testing psFried/roman-numerals-rust against beta-2020-06-03 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpsFried%2Froman-numerals-rust" "/workspace/builds/worker-7/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/psFried/roman-numerals-rust on toolchain beta-2020-06-03
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/psFried/roman-numerals-rust
[INFO] finished tweaking git repo https://github.com/psFried/roman-numerals-rust
[INFO] tweaked toml for git repo https://github.com/psFried/roman-numerals-rust written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/psFried/roman-numerals-rust already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-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" "+beta-2020-06-03" "build" "--frozen"`
[INFO] [stdout] 620f9d09aa364b91555190e764485ea671e102f800e38cebd73dd13b1d2c0f33
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "620f9d09aa364b91555190e764485ea671e102f800e38cebd73dd13b1d2c0f33"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling roman v0.0.1 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0432]: unresolved import `std::slice::SliceConcatExt`
[INFO] [stderr]  --> src/main.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 | use std::slice::SliceConcatExt;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ no `SliceConcatExt` in `slice`
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find function `set_exit_status` in module `std::env`
[INFO] [stderr]   --> src/main.rs:27:15
[INFO] [stderr]    |
[INFO] [stderr] 27 |     std::env::set_exit_status(1);
[INFO] [stderr]    |               ^^^^^^^^^^^^^^^ not found in `std::env`
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(collections)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/main.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(exit_status)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0425, E0432, E0554.
[INFO] [stderr] For more information about an error, try `rustc --explain E0425`.
[INFO] [stderr] error: could not compile `roman`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "620f9d09aa364b91555190e764485ea671e102f800e38cebd73dd13b1d2c0f33"`
[INFO] running `"docker" "rm" "-f" "620f9d09aa364b91555190e764485ea671e102f800e38cebd73dd13b1d2c0f33"`
[INFO] [stdout] 620f9d09aa364b91555190e764485ea671e102f800e38cebd73dd13b1d2c0f33