[INFO] updating cached repository VaclavStebra/rust-book-references-and-borrowing
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/VaclavStebra/rust-book-references-and-borrowing
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/VaclavStebra/rust-book-references-and-borrowing" "work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/VaclavStebra/rust-book-references-and-borrowing" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/VaclavStebra/rust-book-references-and-borrowing"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/VaclavStebra/rust-book-references-and-borrowing'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 6a69d6a3a909d36b8b69bc865641a6b3053066d0
[INFO] sha for GitHub repo VaclavStebra/rust-book-references-and-borrowing: 6a69d6a3a909d36b8b69bc865641a6b3053066d0
[INFO] validating manifest of VaclavStebra/rust-book-references-and-borrowing 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 VaclavStebra/rust-book-references-and-borrowing 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 VaclavStebra/rust-book-references-and-borrowing
[INFO] finished frobbing VaclavStebra/rust-book-references-and-borrowing
[INFO] frobbed toml for VaclavStebra/rust-book-references-and-borrowing written to work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing/Cargo.toml
[INFO] started frobbing VaclavStebra/rust-book-references-and-borrowing
[INFO] finished frobbing VaclavStebra/rust-book-references-and-borrowing
[INFO] frobbed toml for VaclavStebra/rust-book-references-and-borrowing written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/VaclavStebra/rust-book-references-and-borrowing/Cargo.toml
[INFO] crate VaclavStebra/rust-book-references-and-borrowing 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 VaclavStebra/rust-book-references-and-borrowing 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-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing:/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] 2310ac5b36503e6928cd16e8d80972f2b30d3f22cd398a36eb2fe30ce5eebd17
[INFO] running `"docker" "start" "-a" "2310ac5b36503e6928cd16e8d80972f2b30d3f22cd398a36eb2fe30ce5eebd17"`
[INFO] [stderr]    Compiling rust-book-references-and-borrowing v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `r1`
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let r1 = &mut s2;
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_r1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.76s
[INFO] running `"docker" "inspect" "2310ac5b36503e6928cd16e8d80972f2b30d3f22cd398a36eb2fe30ce5eebd17"`
[INFO] running `"docker" "rm" "-f" "2310ac5b36503e6928cd16e8d80972f2b30d3f22cd398a36eb2fe30ce5eebd17"`
[INFO] [stdout] 2310ac5b36503e6928cd16e8d80972f2b30d3f22cd398a36eb2fe30ce5eebd17
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing:/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" "test" "--frozen" "--no-run"`
[INFO] [stdout] 0be58be7bd0bf8c8ffda12d7db5c500d6025efe33679cacf870b245a8efa1820
[INFO] running `"docker" "start" "-a" "0be58be7bd0bf8c8ffda12d7db5c500d6025efe33679cacf870b245a8efa1820"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rust-book-references-and-borrowing v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `r1`
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let r1 = &mut s2;
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_r1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.64s
[INFO] running `"docker" "inspect" "0be58be7bd0bf8c8ffda12d7db5c500d6025efe33679cacf870b245a8efa1820"`
[INFO] running `"docker" "rm" "-f" "0be58be7bd0bf8c8ffda12d7db5c500d6025efe33679cacf870b245a8efa1820"`
[INFO] [stdout] 0be58be7bd0bf8c8ffda12d7db5c500d6025efe33679cacf870b245a8efa1820
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/VaclavStebra/rust-book-references-and-borrowing:/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" "test" "--frozen"`
[INFO] [stdout] fef66b2e342ac2775f48171f66005d019d4aeac80a1f187af03428675eb24bd5
[INFO] running `"docker" "start" "-a" "fef66b2e342ac2775f48171f66005d019d4aeac80a1f187af03428675eb24bd5"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/crater/target/debug/deps/rust_book_references_and_borrowing-7b26c2214c0e1a1b
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "fef66b2e342ac2775f48171f66005d019d4aeac80a1f187af03428675eb24bd5"`
[INFO] running `"docker" "rm" "-f" "fef66b2e342ac2775f48171f66005d019d4aeac80a1f187af03428675eb24bd5"`
[INFO] [stdout] fef66b2e342ac2775f48171f66005d019d4aeac80a1f187af03428675eb24bd5