[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-1.38-1/sources/1.37.0/gh/learn-you-a-rust/slices"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/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-1.38-1/sources/beta-2019-08-13/gh/learn-you-a-rust/slices"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/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 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of learn-you-a-rust/slices 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 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-1.38-1/sources/1.37.0/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-1.38-1/sources/beta-2019-08-13/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" "+1.37.0" "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 learn-you-a-rust/slices 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-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 2d83e0add353bffd962ded7a538c093a7f42ce92b815be6e50a1a9da1869bf0d
[INFO] running `"docker" "start" "-a" "2d83e0add353bffd962ded7a538c093a7f42ce92b815be6e50a1a9da1869bf0d"`
[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 0.34s
[INFO] running `"docker" "inspect" "2d83e0add353bffd962ded7a538c093a7f42ce92b815be6e50a1a9da1869bf0d"`
[INFO] running `"docker" "rm" "-f" "2d83e0add353bffd962ded7a538c093a7f42ce92b815be6e50a1a9da1869bf0d"`
[INFO] [stdout] 2d83e0add353bffd962ded7a538c093a7f42ce92b815be6e50a1a9da1869bf0d
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/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" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 585ce2b90e54750cb0a5a1636ca81c47f828a56a5c006f3484a70e62acfbe3a6
[INFO] running `"docker" "start" "-a" "585ce2b90e54750cb0a5a1636ca81c47f828a56a5c006f3484a70e62acfbe3a6"`
[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 0.30s
[INFO] running `"docker" "inspect" "585ce2b90e54750cb0a5a1636ca81c47f828a56a5c006f3484a70e62acfbe3a6"`
[INFO] running `"docker" "rm" "-f" "585ce2b90e54750cb0a5a1636ca81c47f828a56a5c006f3484a70e62acfbe3a6"`
[INFO] [stdout] 585ce2b90e54750cb0a5a1636ca81c47f828a56a5c006f3484a70e62acfbe3a6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/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" "+1.37.0" "test" "--frozen"`
[INFO] [stdout] ee1313a81c8e02160d28098b4e413d0730fa65b48ec7fc15f9d8ec6cb8c6cd47
[INFO] running `"docker" "start" "-a" "ee1313a81c8e02160d28098b4e413d0730fa65b48ec7fc15f9d8ec6cb8c6cd47"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/slices-c436c56345bf6d5c
[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" "ee1313a81c8e02160d28098b4e413d0730fa65b48ec7fc15f9d8ec6cb8c6cd47"`
[INFO] running `"docker" "rm" "-f" "ee1313a81c8e02160d28098b4e413d0730fa65b48ec7fc15f9d8ec6cb8c6cd47"`
[INFO] [stdout] ee1313a81c8e02160d28098b4e413d0730fa65b48ec7fc15f9d8ec6cb8c6cd47