[INFO] updating cached repository bensu/rust_intro_to_algo
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/bensu/rust_intro_to_algo
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/bensu/rust_intro_to_algo" "work/ex/pr-61100/sources/master#8869ee03d7f258e1b76a11c6fbb01b5708a9f504/gh/bensu/rust_intro_to_algo"`
[INFO] [stderr] Cloning into 'work/ex/pr-61100/sources/master#8869ee03d7f258e1b76a11c6fbb01b5708a9f504/gh/bensu/rust_intro_to_algo'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/bensu/rust_intro_to_algo" "work/ex/pr-61100/sources/try#58b21121d0b447ceb3f1a655155d802191acf044/gh/bensu/rust_intro_to_algo"`
[INFO] [stderr] Cloning into 'work/ex/pr-61100/sources/try#58b21121d0b447ceb3f1a655155d802191acf044/gh/bensu/rust_intro_to_algo'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 82414741f1fc0e81fe23add8204da486fbdf6322
[INFO] sha for GitHub repo bensu/rust_intro_to_algo: 82414741f1fc0e81fe23add8204da486fbdf6322
[INFO] validating manifest of bensu/rust_intro_to_algo on toolchain master#8869ee03d7f258e1b76a11c6fbb01b5708a9f504
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+8869ee03d7f258e1b76a11c6fbb01b5708a9f504-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of bensu/rust_intro_to_algo on toolchain try#58b21121d0b447ceb3f1a655155d802191acf044
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+58b21121d0b447ceb3f1a655155d802191acf044-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing bensu/rust_intro_to_algo
[INFO] finished frobbing bensu/rust_intro_to_algo
[INFO] frobbed toml for bensu/rust_intro_to_algo written to work/ex/pr-61100/sources/master#8869ee03d7f258e1b76a11c6fbb01b5708a9f504/gh/bensu/rust_intro_to_algo/Cargo.toml
[INFO] started frobbing bensu/rust_intro_to_algo
[INFO] finished frobbing bensu/rust_intro_to_algo
[INFO] frobbed toml for bensu/rust_intro_to_algo written to work/ex/pr-61100/sources/try#58b21121d0b447ceb3f1a655155d802191acf044/gh/bensu/rust_intro_to_algo/Cargo.toml
[INFO] crate bensu/rust_intro_to_algo already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+8869ee03d7f258e1b76a11c6fbb01b5708a9f504-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: the lock file /mnt/crater-raid/crater/work/ex/pr-61100/sources/master#8869ee03d7f258e1b76a11c6fbb01b5708a9f504/gh/bensu/rust_intro_to_algo/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+8869ee03d7f258e1b76a11c6fbb01b5708a9f504-alt" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+58b21121d0b447ceb3f1a655155d802191acf044-alt" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+8869ee03d7f258e1b76a11c6fbb01b5708a9f504-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+58b21121d0b447ceb3f1a655155d802191acf044-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] checking bensu/rust_intro_to_algo against try#58b21121d0b447ceb3f1a655155d802191acf044 for pr-61100
[INFO] running `"docker" "create" "-v" "/mnt/crater-raid/crater/work/local/target-dirs/pr-61100/worker-7/try#58b21121d0b447ceb3f1a655155d802191acf044:/opt/crater/target:rw,Z" "-v" "/mnt/crater-raid/crater/work/ex/pr-61100/sources/try#58b21121d0b447ceb3f1a655155d802191acf044/gh/bensu/rust_intro_to_algo:/opt/crater/workdir:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/crater-raid/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" "+58b21121d0b447ceb3f1a655155d802191acf044-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 90ca38e715c317d6d0df2130935492f6fe4abc208771c9e0a3ff07abfcff918d
[INFO] running `"docker" "start" "-a" "90ca38e715c317d6d0df2130935492f6fe4abc208771c9e0a3ff07abfcff918d"`
[INFO] [stderr]     Checking union_find v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `i`
[INFO] [stderr]   --> src/util.rs:15:9
[INFO] [stderr]    |
[INFO] [stderr] 15 |     for i in 0..n {
[INFO] [stderr]    |         ^ help: consider prefixing with an underscore: `_i`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `is_sorted`
[INFO] [stderr]   --> src/util.rs:21:1
[INFO] [stderr]    |
[INFO] [stderr] 21 | pub fn is_sorted<T: Ord>(a: &[T]) -> bool {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `i`
[INFO] [stderr]   --> src/util.rs:15:9
[INFO] [stderr]    |
[INFO] [stderr] 15 |     for i in 0..n {
[INFO] [stderr]    |         ^ help: consider prefixing with an underscore: `_i`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `is_sorted`
[INFO] [stderr]   --> src/util.rs:21:1
[INFO] [stderr]    |
[INFO] [stderr] 21 | pub fn is_sorted<T: Ord>(a: &[T]) -> bool {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.92s
[INFO] running `"docker" "inspect" "90ca38e715c317d6d0df2130935492f6fe4abc208771c9e0a3ff07abfcff918d"`
[INFO] running `"docker" "rm" "-f" "90ca38e715c317d6d0df2130935492f6fe4abc208771c9e0a3ff07abfcff918d"`
[INFO] [stdout] 90ca38e715c317d6d0df2130935492f6fe4abc208771c9e0a3ff07abfcff918d