[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] testing learn-you-a-rust/slices against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Fslices" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/slices on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", 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-10/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" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1a06bb0f934ea2552559807c09260f369c5810faff89b2d4d48f2cf24d97955a
[INFO] running `Command { std: "docker" "start" "-a" "1a06bb0f934ea2552559807c09260f369c5810faff89b2d4d48f2cf24d97955a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1a06bb0f934ea2552559807c09260f369c5810faff89b2d4d48f2cf24d97955a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1a06bb0f934ea2552559807c09260f369c5810faff89b2d4d48f2cf24d97955a", kill_on_drop: false }`
[INFO] [stdout] 1a06bb0f934ea2552559807c09260f369c5810faff89b2d4d48f2cf24d97955a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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=warn" "-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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6fb3aa50a084789cd72e6f7140cf74e687ba10163afabc859d9c2cabdcd433a5
[INFO] running `Command { std: "docker" "start" "-a" "6fb3aa50a084789cd72e6f7140cf74e687ba10163afabc859d9c2cabdcd433a5", kill_on_drop: false }`
[INFO] [stderr]    Compiling 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: 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: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.28s
[INFO] running `Command { std: "docker" "inspect" "6fb3aa50a084789cd72e6f7140cf74e687ba10163afabc859d9c2cabdcd433a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6fb3aa50a084789cd72e6f7140cf74e687ba10163afabc859d9c2cabdcd433a5", kill_on_drop: false }`
[INFO] [stdout] 6fb3aa50a084789cd72e6f7140cf74e687ba10163afabc859d9c2cabdcd433a5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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=warn" "-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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e1a62b28230c9fcfcd56c6597f2242e85789f0834a183b8a3f80c0de822cf227
[INFO] running `Command { std: "docker" "start" "-a" "e1a62b28230c9fcfcd56c6597f2242e85789f0834a183b8a3f80c0de822cf227", kill_on_drop: false }`
[INFO] [stderr]    Compiling 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: 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: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.29s
[INFO] running `Command { std: "docker" "inspect" "e1a62b28230c9fcfcd56c6597f2242e85789f0834a183b8a3f80c0de822cf227", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e1a62b28230c9fcfcd56c6597f2242e85789f0834a183b8a3f80c0de822cf227", kill_on_drop: false }`
[INFO] [stdout] e1a62b28230c9fcfcd56c6597f2242e85789f0834a183b8a3f80c0de822cf227
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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=warn" "-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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 8f7154eafcb206c31470274b51623df0e117414ad954080cd09a145b1f23b6ce
[INFO] running `Command { std: "docker" "start" "-a" "8f7154eafcb206c31470274b51623df0e117414ad954080cd09a145b1f23b6ce", kill_on_drop: false }`
[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: if this is intentional, prefix it 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:69:4
[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: `slices` (bin "slices" test) generated 3 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/slices-0c304ef36844d1f3)
[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; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "8f7154eafcb206c31470274b51623df0e117414ad954080cd09a145b1f23b6ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8f7154eafcb206c31470274b51623df0e117414ad954080cd09a145b1f23b6ce", kill_on_drop: false }`
[INFO] [stdout] 8f7154eafcb206c31470274b51623df0e117414ad954080cd09a145b1f23b6ce