[INFO] updating cached repository psFried/roman-numerals-rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/psFried/roman-numerals-rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/psFried/roman-numerals-rust" "work/ex/beta-1.38-1/sources/1.37.0/gh/psFried/roman-numerals-rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/psFried/roman-numerals-rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/psFried/roman-numerals-rust" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/psFried/roman-numerals-rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/psFried/roman-numerals-rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] a5eb19ba0468ee970bf2118998631a74df84ab43
[INFO] sha for GitHub repo psFried/roman-numerals-rust: a5eb19ba0468ee970bf2118998631a74df84ab43
[INFO] validating manifest of psFried/roman-numerals-rust 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 psFried/roman-numerals-rust 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 psFried/roman-numerals-rust
[INFO] finished frobbing psFried/roman-numerals-rust
[INFO] frobbed toml for psFried/roman-numerals-rust written to work/ex/beta-1.38-1/sources/1.37.0/gh/psFried/roman-numerals-rust/Cargo.toml
[INFO] started frobbing psFried/roman-numerals-rust
[INFO] finished frobbing psFried/roman-numerals-rust
[INFO] frobbed toml for psFried/roman-numerals-rust written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/psFried/roman-numerals-rust/Cargo.toml
[INFO] crate psFried/roman-numerals-rust 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 psFried/roman-numerals-rust 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-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/psFried/roman-numerals-rust:/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] 2a5c8a3670b4aebea85e8a7f1ae17fd2c21ae01ff547e09e7f23f00c235ac4e8
[INFO] running `"docker" "start" "-a" "2a5c8a3670b4aebea85e8a7f1ae17fd2c21ae01ff547e09e7f23f00c235ac4e8"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling roman v0.0.1 (/opt/crater/workdir)
[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 stable 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 stable release channel
[INFO] [stderr]  --> src/main.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(exit_status)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'slice_concat_ext': trait should not have to exist
[INFO] [stderr]  --> src/main.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 | use std::slice::SliceConcatExt;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: for more information, see https://github.com/rust-lang/rust/issues/27747
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0425, E0554, E0658.
[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" "2a5c8a3670b4aebea85e8a7f1ae17fd2c21ae01ff547e09e7f23f00c235ac4e8"`
[INFO] running `"docker" "rm" "-f" "2a5c8a3670b4aebea85e8a7f1ae17fd2c21ae01ff547e09e7f23f00c235ac4e8"`
[INFO] [stdout] 2a5c8a3670b4aebea85e8a7f1ae17fd2c21ae01ff547e09e7f23f00c235ac4e8