[INFO] updating cached repository TheMegaTB/backtracking
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/TheMegaTB/backtracking
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/TheMegaTB/backtracking" "work/ex/pr-63247/sources/master#452087b4bf18cece2d52d7cd8c9147195e5404bf/gh/TheMegaTB/backtracking"`
[INFO] [stderr] Cloning into 'work/ex/pr-63247/sources/master#452087b4bf18cece2d52d7cd8c9147195e5404bf/gh/TheMegaTB/backtracking'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/TheMegaTB/backtracking" "work/ex/pr-63247/sources/try#757dacae0a9f1b46b3ab58a1f1232332e8fc7dab/gh/TheMegaTB/backtracking"`
[INFO] [stderr] Cloning into 'work/ex/pr-63247/sources/try#757dacae0a9f1b46b3ab58a1f1232332e8fc7dab/gh/TheMegaTB/backtracking'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] d147bd5645bdedd8da4983566e1705df1cbb82ac
[INFO] sha for GitHub repo TheMegaTB/backtracking: d147bd5645bdedd8da4983566e1705df1cbb82ac
[INFO] validating manifest of TheMegaTB/backtracking on toolchain master#452087b4bf18cece2d52d7cd8c9147195e5404bf
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+452087b4bf18cece2d52d7cd8c9147195e5404bf-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of TheMegaTB/backtracking on toolchain try#757dacae0a9f1b46b3ab58a1f1232332e8fc7dab
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+757dacae0a9f1b46b3ab58a1f1232332e8fc7dab-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing TheMegaTB/backtracking
[INFO] finished frobbing TheMegaTB/backtracking
[INFO] frobbed toml for TheMegaTB/backtracking written to work/ex/pr-63247/sources/master#452087b4bf18cece2d52d7cd8c9147195e5404bf/gh/TheMegaTB/backtracking/Cargo.toml
[INFO] started frobbing TheMegaTB/backtracking
[INFO] finished frobbing TheMegaTB/backtracking
[INFO] frobbed toml for TheMegaTB/backtracking written to work/ex/pr-63247/sources/try#757dacae0a9f1b46b3ab58a1f1232332e8fc7dab/gh/TheMegaTB/backtracking/Cargo.toml
[INFO] crate TheMegaTB/backtracking already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+452087b4bf18cece2d52d7cd8c9147195e5404bf-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: the lock file /mnt/big/crater/work/ex/pr-63247/sources/master#452087b4bf18cece2d52d7cd8c9147195e5404bf/gh/TheMegaTB/backtracking/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+452087b4bf18cece2d52d7cd8c9147195e5404bf-alt" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+757dacae0a9f1b46b3ab58a1f1232332e8fc7dab-alt" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+452087b4bf18cece2d52d7cd8c9147195e5404bf-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+757dacae0a9f1b46b3ab58a1f1232332e8fc7dab-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking TheMegaTB/backtracking against master#452087b4bf18cece2d52d7cd8c9147195e5404bf for pr-63247
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-63247/worker-2/master#452087b4bf18cece2d52d7cd8c9147195e5404bf:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/pr-63247/sources/master#452087b4bf18cece2d52d7cd8c9147195e5404bf/gh/TheMegaTB/backtracking:/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" "+452087b4bf18cece2d52d7cd8c9147195e5404bf-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 502db2ea28f723f235b5cb1d3a443d69d6a4faef045d6854d6cb7d37f9cc4f96
[INFO] running `"docker" "start" "-a" "502db2ea28f723f235b5cb1d3a443d69d6a4faef045d6854d6cb7d37f9cc4f96"`
[INFO] [stderr]     Checking backtracking v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: use of deprecated item 'std::thread::sleep_ms': replaced by `std::thread::sleep`
[INFO] [stderr]    --> src/main.rs:206:5
[INFO] [stderr]     |
[INFO] [stderr] 206 |     std::thread::sleep_ms(250);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(deprecated)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: use of deprecated item 'std::thread::sleep_ms': replaced by `std::thread::sleep`
[INFO] [stderr]    --> src/main.rs:206:5
[INFO] [stderr]     |
[INFO] [stderr] 206 |     std::thread::sleep_ms(250);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(deprecated)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `print_blocked`
[INFO] [stderr]   --> src/main.rs:95:1
[INFO] [stderr]    |
[INFO] [stderr] 95 | fn print_blocked(m: &Maze) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `print_blocked`
[INFO] [stderr]   --> src/main.rs:95:1
[INFO] [stderr]    |
[INFO] [stderr] 95 | fn print_blocked(m: &Maze) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.89s
[INFO] running `"docker" "inspect" "502db2ea28f723f235b5cb1d3a443d69d6a4faef045d6854d6cb7d37f9cc4f96"`
[INFO] running `"docker" "rm" "-f" "502db2ea28f723f235b5cb1d3a443d69d6a4faef045d6854d6cb7d37f9cc4f96"`
[INFO] [stdout] 502db2ea28f723f235b5cb1d3a443d69d6a4faef045d6854d6cb7d37f9cc4f96