[INFO] updating cached repository https://github.com/learn-you-a-rust/slices
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/mnt/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 0ef7968cbbf4b775de9a1e444a73b264c73876d0
[INFO] checking learn-you-a-rust/slices against try#e689e5eaefe96e6dc3ed5bb629c521b7d207aff7 for pr-64398
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Fslices" "work/builds/worker-1/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/slices on toolchain e689e5eaefe96e6dc3ed5bb629c521b7d207aff7-alt
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+e689e5eaefe96e6dc3ed5bb629c521b7d207aff7-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/learn-you-a-rust/slices
[INFO] finished tweaking git repo https://github.com/learn-you-a-rust/slices
[INFO] tweaked toml for git repo https://github.com/learn-you-a-rust/slices written to work/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/learn-you-a-rust/slices already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+e689e5eaefe96e6dc3ed5bb629c521b7d207aff7-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/mnt/big/crater/work/builds/worker-1/source:/opt/rustwide/workdir:ro,Z" "-v" "/mnt/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+e689e5eaefe96e6dc3ed5bb629c521b7d207aff7-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 9f261ccc962c7ce04fe602156953b8597f6cf41b4ce3795d75048b9b9d0a1643
[INFO] running `"docker" "start" "-a" "9f261ccc962c7ce04fe602156953b8597f6cf41b4ce3795d75048b9b9d0a1643"`
[INFO] [stderr]     Checking slices v0.1.0 (/opt/rustwide/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] 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 0.70s
[INFO] running `"docker" "inspect" "9f261ccc962c7ce04fe602156953b8597f6cf41b4ce3795d75048b9b9d0a1643"`
[INFO] running `"docker" "rm" "-f" "9f261ccc962c7ce04fe602156953b8597f6cf41b4ce3795d75048b9b9d0a1643"`
[INFO] [stdout] 9f261ccc962c7ce04fe602156953b8597f6cf41b4ce3795d75048b9b9d0a1643