[INFO] updating cached repository learn-you-a-rust/slices
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/learn-you-a-rust/slices
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/learn-you-a-rust/slices" "work/ex/beta-1.37-6/sources/1.36.0/gh/learn-you-a-rust/slices"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/learn-you-a-rust/slices'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/learn-you-a-rust/slices" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 0ef7968cbbf4b775de9a1e444a73b264c73876d0
[INFO] sha for GitHub repo learn-you-a-rust/slices: 0ef7968cbbf4b775de9a1e444a73b264c73876d0
[INFO] validating manifest of learn-you-a-rust/slices on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of learn-you-a-rust/slices on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing learn-you-a-rust/slices
[INFO] finished frobbing learn-you-a-rust/slices
[INFO] frobbed toml for learn-you-a-rust/slices written to work/ex/beta-1.37-6/sources/1.36.0/gh/learn-you-a-rust/slices/Cargo.toml
[INFO] started frobbing learn-you-a-rust/slices
[INFO] finished frobbing learn-you-a-rust/slices
[INFO] frobbed toml for learn-you-a-rust/slices written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices/Cargo.toml
[INFO] crate learn-you-a-rust/slices already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing learn-you-a-rust/slices against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices:/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-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 63179dd9a66a86bccf9e5d1a5a2c46bd63d1d0bbbfc647c726c770a1b4a41fd8
[INFO] running `"docker" "start" "-a" "63179dd9a66a86bccf9e5d1a5a2c46bd63d1d0bbbfc647c726c770a1b4a41fd8"`
[INFO] [stderr]    Compiling slices v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `a_slice`
[INFO] [stderr]   --> src/main.rs:49:9
[INFO] [stderr]    |
[INFO] [stderr] 49 |     let a_slice = &array[1..3];
[INFO] [stderr]    |         ^^^^^^^ help: consider prefixing with an underscore: `_a_slice`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let mut t = String::from("hello, kitty");
[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] warning: function is never used: `first_word`
[INFO] [stderr]   --> src/main.rs:69:1
[INFO] [stderr]    |
[INFO] [stderr] 69 | fn first_word(s: &String) -> usize {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.42s
[INFO] running `"docker" "inspect" "63179dd9a66a86bccf9e5d1a5a2c46bd63d1d0bbbfc647c726c770a1b4a41fd8"`
[INFO] running `"docker" "rm" "-f" "63179dd9a66a86bccf9e5d1a5a2c46bd63d1d0bbbfc647c726c770a1b4a41fd8"`
[INFO] [stdout] 63179dd9a66a86bccf9e5d1a5a2c46bd63d1d0bbbfc647c726c770a1b4a41fd8
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices:/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-2019-07-23" "test" "--frozen" "--no-run"`
[INFO] [stdout] cea69da5f3270ae13f3841f64a1fbcb678a23d1221ee5c29b18b44e7cebd2ebf
[INFO] running `"docker" "start" "-a" "cea69da5f3270ae13f3841f64a1fbcb678a23d1221ee5c29b18b44e7cebd2ebf"`
[INFO] [stderr]    Compiling slices v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `a_slice`
[INFO] [stderr]   --> src/main.rs:49:9
[INFO] [stderr]    |
[INFO] [stderr] 49 |     let a_slice = &array[1..3];
[INFO] [stderr]    |         ^^^^^^^ help: consider prefixing with an underscore: `_a_slice`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let mut t = String::from("hello, kitty");
[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] warning: function is never used: `first_word`
[INFO] [stderr]   --> src/main.rs:69:1
[INFO] [stderr]    |
[INFO] [stderr] 69 | fn first_word(s: &String) -> usize {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.48s
[INFO] running `"docker" "inspect" "cea69da5f3270ae13f3841f64a1fbcb678a23d1221ee5c29b18b44e7cebd2ebf"`
[INFO] running `"docker" "rm" "-f" "cea69da5f3270ae13f3841f64a1fbcb678a23d1221ee5c29b18b44e7cebd2ebf"`
[INFO] [stdout] cea69da5f3270ae13f3841f64a1fbcb678a23d1221ee5c29b18b44e7cebd2ebf
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/learn-you-a-rust/slices:/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-2019-07-23" "test" "--frozen"`
[INFO] [stdout] bfd4c031bbb7420cb69b07b90a32b4d67094fae7b38e511b066e8923e4c66eb7
[INFO] running `"docker" "start" "-a" "bfd4c031bbb7420cb69b07b90a32b4d67094fae7b38e511b066e8923e4c66eb7"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/slices-5a8d569f52fd104c
[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" "bfd4c031bbb7420cb69b07b90a32b4d67094fae7b38e511b066e8923e4c66eb7"`
[INFO] running `"docker" "rm" "-f" "bfd4c031bbb7420cb69b07b90a32b4d67094fae7b38e511b066e8923e4c66eb7"`
[INFO] [stdout] bfd4c031bbb7420cb69b07b90a32b4d67094fae7b38e511b066e8923e4c66eb7