[INFO] cloning repository https://github.com/learn-you-a-rust/slices
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/learn-you-a-rust/slices" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Fslices", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Fslices'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0ef7968cbbf4b775de9a1e444a73b264c73876d0
[INFO] checking learn-you-a-rust/slices against master#0dce3f606e05cffab7361c132a399d3550ab0df8 for pr-78376
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Fslices" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/slices on toolchain 0dce3f606e05cffab7361c132a399d3550ab0df8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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 /workspace/builds/worker-3/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 `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 87c6dff61153103db6bd9f652e5b4b3e49be34769e238a95df6cab420c262fa3
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "87c6dff61153103db6bd9f652e5b4b3e49be34769e238a95df6cab420c262fa3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "87c6dff61153103db6bd9f652e5b4b3e49be34769e238a95df6cab420c262fa3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "87c6dff61153103db6bd9f652e5b4b3e49be34769e238a95df6cab420c262fa3", kill_on_drop: false }`
[INFO] [stdout] 87c6dff61153103db6bd9f652e5b4b3e49be34769e238a95df6cab420c262fa3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-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" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 367bb17389345f478b6fe014fbd3c5cca8d195046e4f49720e9cd1e5f475b334
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "367bb17389345f478b6fe014fbd3c5cca8d195046e4f49720e9cd1e5f475b334", kill_on_drop: false }`
[INFO] [stderr]     Checking slices v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `a_slice`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let a_slice = &array[1..3];
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_slice`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a_slice`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let a_slice = &array[1..3];
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_slice`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut t = String::from("hello, kitty");
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut t = String::from("hello, kitty");
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `first_word`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn first_word(s: &String) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `first_word`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn first_word(s: &String) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.26s
[INFO] running `Command { std: "docker" "inspect" "367bb17389345f478b6fe014fbd3c5cca8d195046e4f49720e9cd1e5f475b334", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "367bb17389345f478b6fe014fbd3c5cca8d195046e4f49720e9cd1e5f475b334", kill_on_drop: false }`
[INFO] [stdout] 367bb17389345f478b6fe014fbd3c5cca8d195046e4f49720e9cd1e5f475b334