[INFO] updating cached repository Flecheck/Sudoku
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Flecheck/Sudoku
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Flecheck/Sudoku" "work/ex/pr-57745/sources/master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039/gh/Flecheck/Sudoku"`
[INFO] [stderr] Cloning into 'work/ex/pr-57745/sources/master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039/gh/Flecheck/Sudoku'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Flecheck/Sudoku" "work/ex/pr-57745/sources/try#29640c57b5f92febba0e40c50cb863c9a7ede51d/gh/Flecheck/Sudoku"`
[INFO] [stderr] Cloning into 'work/ex/pr-57745/sources/try#29640c57b5f92febba0e40c50cb863c9a7ede51d/gh/Flecheck/Sudoku'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] b4d750cdaf93f8ab6a4f354cec2008b75ebcf1b5
[INFO] sha for GitHub repo Flecheck/Sudoku: b4d750cdaf93f8ab6a4f354cec2008b75ebcf1b5
[INFO] validating manifest of Flecheck/Sudoku on toolchain master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+f613dc138b4012cf3d2eb40718fbcc7cf0a34039-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of Flecheck/Sudoku on toolchain try#29640c57b5f92febba0e40c50cb863c9a7ede51d
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+29640c57b5f92febba0e40c50cb863c9a7ede51d-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing Flecheck/Sudoku
[INFO] finished frobbing Flecheck/Sudoku
[INFO] frobbed toml for Flecheck/Sudoku written to work/ex/pr-57745/sources/master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039/gh/Flecheck/Sudoku/Cargo.toml
[INFO] started frobbing Flecheck/Sudoku
[INFO] finished frobbing Flecheck/Sudoku
[INFO] frobbed toml for Flecheck/Sudoku written to work/ex/pr-57745/sources/try#29640c57b5f92febba0e40c50cb863c9a7ede51d/gh/Flecheck/Sudoku/Cargo.toml
[INFO] crate Flecheck/Sudoku has a lockfile. skipping
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+f613dc138b4012cf3d2eb40718fbcc7cf0a34039-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+29640c57b5f92febba0e40c50cb863c9a7ede51d-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking Flecheck/Sudoku against master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039 for pr-57745
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-57745/worker-2/master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/pr-57745/sources/master#f613dc138b4012cf3d2eb40718fbcc7cf0a34039/gh/Flecheck/Sudoku:/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" "+f613dc138b4012cf3d2eb40718fbcc7cf0a34039-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 3cd48a9968e786a656695f1a75a8ce36f828ef3040a842df6d36c922aa4470fa
[INFO] running `"docker" "start" "-a" "3cd48a9968e786a656695f1a75a8ce36f828ef3040a842df6d36c922aa4470fa"`
[INFO] [stderr]     Checking indexmap v0.4.1
[INFO] [stderr]     Checking priority-queue v0.5.1
[INFO] [stderr]     Checking sudoku v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused import: `std::time::Duration`
[INFO] [stderr]   --> src/main.rs:16:5
[INFO] [stderr]    |
[INFO] [stderr] 16 | use std::time::Duration;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::time::Instant`
[INFO] [stderr]   --> src/main.rs:17:5
[INFO] [stderr]    |
[INFO] [stderr] 17 | use std::time::Instant;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::time::Duration`
[INFO] [stderr]   --> src/main.rs:16:5
[INFO] [stderr]    |
[INFO] [stderr] 16 | use std::time::Duration;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::time::Instant`
[INFO] [stderr]   --> src/main.rs:17:5
[INFO] [stderr]    |
[INFO] [stderr] 17 | use std::time::Instant;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:43:9
[INFO] [stderr]    |
[INFO] [stderr] 43 |         writeln!(stdout, "{}", res);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_must_use)] on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:43:9
[INFO] [stderr]    |
[INFO] [stderr] 43 |         writeln!(stdout, "{}", res);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_must_use)] on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.08s
[INFO] running `"docker" "inspect" "3cd48a9968e786a656695f1a75a8ce36f828ef3040a842df6d36c922aa4470fa"`
[INFO] running `"docker" "rm" "-f" "3cd48a9968e786a656695f1a75a8ce36f828ef3040a842df6d36c922aa4470fa"`
[INFO] [stdout] 3cd48a9968e786a656695f1a75a8ce36f828ef3040a842df6d36c922aa4470fa