[INFO] updating cached repository suelz/chapter_4
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/suelz/chapter_4
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/suelz/chapter_4" "work/ex/pr-62849/sources/master#435236b8877cdb98c82eaebfb7887782277265c5/gh/suelz/chapter_4"`
[INFO] [stderr] Cloning into 'work/ex/pr-62849/sources/master#435236b8877cdb98c82eaebfb7887782277265c5/gh/suelz/chapter_4'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/suelz/chapter_4" "work/ex/pr-62849/sources/try#b5c7f157c20453dde8d47371abe73b32351b4e7f/gh/suelz/chapter_4"`
[INFO] [stderr] Cloning into 'work/ex/pr-62849/sources/try#b5c7f157c20453dde8d47371abe73b32351b4e7f/gh/suelz/chapter_4'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 5266a4ada4918881254cc79de937fbc229bb69a4
[INFO] sha for GitHub repo suelz/chapter_4: 5266a4ada4918881254cc79de937fbc229bb69a4
[INFO] validating manifest of suelz/chapter_4 on toolchain master#435236b8877cdb98c82eaebfb7887782277265c5
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+435236b8877cdb98c82eaebfb7887782277265c5-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of suelz/chapter_4 on toolchain try#b5c7f157c20453dde8d47371abe73b32351b4e7f
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+b5c7f157c20453dde8d47371abe73b32351b4e7f-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing suelz/chapter_4
[INFO] finished frobbing suelz/chapter_4
[INFO] frobbed toml for suelz/chapter_4 written to work/ex/pr-62849/sources/master#435236b8877cdb98c82eaebfb7887782277265c5/gh/suelz/chapter_4/Cargo.toml
[INFO] started frobbing suelz/chapter_4
[INFO] finished frobbing suelz/chapter_4
[INFO] frobbed toml for suelz/chapter_4 written to work/ex/pr-62849/sources/try#b5c7f157c20453dde8d47371abe73b32351b4e7f/gh/suelz/chapter_4/Cargo.toml
[INFO] crate suelz/chapter_4 already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+435236b8877cdb98c82eaebfb7887782277265c5-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+b5c7f157c20453dde8d47371abe73b32351b4e7f-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking suelz/chapter_4 against try#b5c7f157c20453dde8d47371abe73b32351b4e7f for pr-62849
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-62849/worker-3/try#b5c7f157c20453dde8d47371abe73b32351b4e7f:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/pr-62849/sources/try#b5c7f157c20453dde8d47371abe73b32351b4e7f/gh/suelz/chapter_4:/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=forbid" "-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" "+b5c7f157c20453dde8d47371abe73b32351b4e7f-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] d3a23c746d2bc4e34d2e90ffcbb4f6e2faabe45c65325a4cf4882676a4eb352a
[INFO] running `"docker" "start" "-a" "d3a23c746d2bc4e34d2e90ffcbb4f6e2faabe45c65325a4cf4882676a4eb352a"`
[INFO] [stderr]     Checking ch4 v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `word`
[INFO] [stderr]   --> src/main.rs:28:9
[INFO] [stderr]    |
[INFO] [stderr] 28 |     let word = first_word(&x);
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_word`
[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:26:9
[INFO] [stderr]    |
[INFO] [stderr] 26 |     let mut x = String::from("Conor Kennedy");
[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: unused variable: `word`
[INFO] [stderr]   --> src/main.rs:28:9
[INFO] [stderr]    |
[INFO] [stderr] 28 |     let word = first_word(&x);
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_word`
[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:26:9
[INFO] [stderr]    |
[INFO] [stderr] 26 |     let mut x = String::from("Conor Kennedy");
[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]     Finished dev [unoptimized + debuginfo] target(s) in 0.57s
[INFO] running `"docker" "inspect" "d3a23c746d2bc4e34d2e90ffcbb4f6e2faabe45c65325a4cf4882676a4eb352a"`
[INFO] running `"docker" "rm" "-f" "d3a23c746d2bc4e34d2e90ffcbb4f6e2faabe45c65325a4cf4882676a4eb352a"`
[INFO] [stdout] d3a23c746d2bc4e34d2e90ffcbb4f6e2faabe45c65325a4cf4882676a4eb352a