[INFO] cloning repository https://github.com/EthanTheMaster/sudoku_solver
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/EthanTheMaster/sudoku_solver" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEthanTheMaster%2Fsudoku_solver"`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEthanTheMaster%2Fsudoku_solver'...
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f0d269d3d954a9b6c82d6d0856dd0175544949f6
[INFO] checking EthanTheMaster/sudoku_solver against try#e4dba30b9b475d8750370c4dfb49b6541990904d for pr-71393
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEthanTheMaster%2Fsudoku_solver" "/workspace/builds/worker-13/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/EthanTheMaster/sudoku_solver on toolchain e4dba30b9b475d8750370c4dfb49b6541990904d
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/EthanTheMaster/sudoku_solver
[INFO] finished tweaking git repo https://github.com/EthanTheMaster/sudoku_solver
[INFO] tweaked toml for git repo https://github.com/EthanTheMaster/sudoku_solver written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/EthanTheMaster/sudoku_solver already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] d3ca8e15940a7d3a3c09de75b83a094c01538d6c4afc72bc7134bd0e1e6471ac
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "d3ca8e15940a7d3a3c09de75b83a094c01538d6c4afc72bc7134bd0e1e6471ac"`
[INFO] [stderr]     Checking sudoku_solver v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `operation`
[INFO] [stderr]   --> src/sudoku_solver_dancinglinks/mod.rs:96:32
[INFO] [stderr]    |
[INFO] [stderr] 96 |         if let NodeType::Field(operation, column_header_id) = node_type {
[INFO] [stderr]    |                                ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_operation`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:100:40
[INFO] [stderr]     |
[INFO] [stderr] 100 |                 NodeType::ColumnHeader(ref mut constraint, ref mut size) => {
[INFO] [stderr]     |                                        ^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `operation`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:119:29
[INFO] [stderr]     |
[INFO] [stderr] 119 |             NodeType::Field(operation, column_header_id) => {
[INFO] [stderr]     |                             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_operation`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:127:36
[INFO] [stderr]     |
[INFO] [stderr] 127 |             NodeType::ColumnHeader(constraint, size) => {
[INFO] [stderr]     |                                    ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:226:44
[INFO] [stderr]     |
[INFO] [stderr] 226 |                     NodeType::ColumnHeader(constraint, ref mut size) => {
[INFO] [stderr]     |                                            ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:269:44
[INFO] [stderr]     |
[INFO] [stderr] 269 |                     NodeType::ColumnHeader(constraint, ref mut size) => {
[INFO] [stderr]     |                                            ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `idx`
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:35:24
[INFO] [stderr]    |
[INFO] [stderr] 35 |             .filter(|&(idx, val)| {
[INFO] [stderr]    |                        ^^^ help: if this is intentional, prefix it with an underscore: `_idx`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `val`
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:37:27
[INFO] [stderr]    |
[INFO] [stderr] 37 |             }).map(|(idx, val)| {
[INFO] [stderr]    |                           ^^^ help: if this is intentional, prefix it with an underscore: `_val`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:34:13
[INFO] [stderr]    |
[INFO] [stderr] 34 |         let mut blank_positions: Vec<usize> = self.board.iter().enumerate()
[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: `operation`
[INFO] [stderr]   --> src/sudoku_solver_dancinglinks/mod.rs:96:32
[INFO] [stderr]    |
[INFO] [stderr] 96 |         if let NodeType::Field(operation, column_header_id) = node_type {
[INFO] [stderr]    |                                ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_operation`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:100:40
[INFO] [stderr]     |
[INFO] [stderr] 100 |                 NodeType::ColumnHeader(ref mut constraint, ref mut size) => {
[INFO] [stderr]     |                                        ^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `operation`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:119:29
[INFO] [stderr]     |
[INFO] [stderr] 119 |             NodeType::Field(operation, column_header_id) => {
[INFO] [stderr]     |                             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_operation`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:127:36
[INFO] [stderr]     |
[INFO] [stderr] 127 |             NodeType::ColumnHeader(constraint, size) => {
[INFO] [stderr]     |                                    ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:226:44
[INFO] [stderr]     |
[INFO] [stderr] 226 |                     NodeType::ColumnHeader(constraint, ref mut size) => {
[INFO] [stderr]     |                                            ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `constraint`
[INFO] [stderr]    --> src/sudoku_solver_dancinglinks/mod.rs:269:44
[INFO] [stderr]     |
[INFO] [stderr] 269 |                     NodeType::ColumnHeader(constraint, ref mut size) => {
[INFO] [stderr]     |                                            ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `idx`
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:35:24
[INFO] [stderr]    |
[INFO] [stderr] 35 |             .filter(|&(idx, val)| {
[INFO] [stderr]    |                        ^^^ help: if this is intentional, prefix it with an underscore: `_idx`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `val`
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:37:27
[INFO] [stderr]    |
[INFO] [stderr] 37 |             }).map(|(idx, val)| {
[INFO] [stderr]    |                           ^^^ help: if this is intentional, prefix it with an underscore: `_val`
[INFO] [stderr] 
[INFO] [stderr] warning: 9 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/sudoku_solver_backtrack/mod.rs:34:13
[INFO] [stderr]    |
[INFO] [stderr] 34 |         let mut blank_positions: Vec<usize> = self.board.iter().enumerate()
[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: 9 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.95s
[INFO] running `"docker" "inspect" "d3ca8e15940a7d3a3c09de75b83a094c01538d6c4afc72bc7134bd0e1e6471ac"`
[INFO] running `"docker" "rm" "-f" "d3ca8e15940a7d3a3c09de75b83a094c01538d6c4afc72bc7134bd0e1e6471ac"`
[INFO] [stdout] d3ca8e15940a7d3a3c09de75b83a094c01538d6c4afc72bc7134bd0e1e6471ac