[INFO] updating cached repository bon-chi/tower_of_hanoi_in_rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/bon-chi/tower_of_hanoi_in_rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/bon-chi/tower_of_hanoi_in_rust" "work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/tower_of_hanoi_in_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/tower_of_hanoi_in_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/bon-chi/tower_of_hanoi_in_rust" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 6db73d2b8c4a3dffb5c55025cbf3bd44d5188ab2
[INFO] sha for GitHub repo bon-chi/tower_of_hanoi_in_rust: 6db73d2b8c4a3dffb5c55025cbf3bd44d5188ab2
[INFO] validating manifest of bon-chi/tower_of_hanoi_in_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 bon-chi/tower_of_hanoi_in_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 bon-chi/tower_of_hanoi_in_rust
[INFO] finished frobbing bon-chi/tower_of_hanoi_in_rust
[INFO] frobbed toml for bon-chi/tower_of_hanoi_in_rust written to work/ex/beta-1.38-1/sources/1.37.0/gh/bon-chi/tower_of_hanoi_in_rust/Cargo.toml
[INFO] started frobbing bon-chi/tower_of_hanoi_in_rust
[INFO] finished frobbing bon-chi/tower_of_hanoi_in_rust
[INFO] frobbed toml for bon-chi/tower_of_hanoi_in_rust written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_rust/Cargo.toml
[INFO] crate bon-chi/tower_of_hanoi_in_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 bon-chi/tower_of_hanoi_in_rust against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_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" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] 0cc8e23114ce0ce2d928fb2f066d71e43554ac4066b38ed79466618fe4437f5c
[INFO] running `"docker" "start" "-a" "0cc8e23114ce0ce2d928fb2f066d71e43554ac4066b38ed79466618fe4437f5c"`
[INFO] [stderr]    Compiling tower_of_hanoi_in_rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:22:9
[INFO] [stderr]    |
[INFO] [stderr] 22 |     let mut new_stream: &mut Vec<i32> = &mut hanoi_stream(n - 1, h1);
[INFO] [stderr]    |         ----^^^^^^^^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.78s
[INFO] running `"docker" "inspect" "0cc8e23114ce0ce2d928fb2f066d71e43554ac4066b38ed79466618fe4437f5c"`
[INFO] running `"docker" "rm" "-f" "0cc8e23114ce0ce2d928fb2f066d71e43554ac4066b38ed79466618fe4437f5c"`
[INFO] [stdout] 0cc8e23114ce0ce2d928fb2f066d71e43554ac4066b38ed79466618fe4437f5c
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_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" "+beta-2019-08-13" "test" "--frozen" "--no-run"`
[INFO] [stdout] e192714905639a3ef87ceb951968cb23619a0651308e7843231930e0f0c7f494
[INFO] running `"docker" "start" "-a" "e192714905639a3ef87ceb951968cb23619a0651308e7843231930e0f0c7f494"`
[INFO] [stderr]    Compiling tower_of_hanoi_in_rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:22:9
[INFO] [stderr]    |
[INFO] [stderr] 22 |     let mut new_stream: &mut Vec<i32> = &mut hanoi_stream(n - 1, h1);
[INFO] [stderr]    |         ----^^^^^^^^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.69s
[INFO] running `"docker" "inspect" "e192714905639a3ef87ceb951968cb23619a0651308e7843231930e0f0c7f494"`
[INFO] running `"docker" "rm" "-f" "e192714905639a3ef87ceb951968cb23619a0651308e7843231930e0f0c7f494"`
[INFO] [stdout] e192714905639a3ef87ceb951968cb23619a0651308e7843231930e0f0c7f494
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/bon-chi/tower_of_hanoi_in_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" "+beta-2019-08-13" "test" "--frozen"`
[INFO] [stdout] 27216f6d75249966aa251b0e90443c43bffc1ea84238f22c09d564beaf66a004
[INFO] running `"docker" "start" "-a" "27216f6d75249966aa251b0e90443c43bffc1ea84238f22c09d564beaf66a004"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/tower_of_hanoi_in_rust-4285dd2a159353a4
[INFO] [stdout] 
[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" "27216f6d75249966aa251b0e90443c43bffc1ea84238f22c09d564beaf66a004"`
[INFO] running `"docker" "rm" "-f" "27216f6d75249966aa251b0e90443c43bffc1ea84238f22c09d564beaf66a004"`
[INFO] [stdout] 27216f6d75249966aa251b0e90443c43bffc1ea84238f22c09d564beaf66a004