[INFO] cloning repository https://github.com/cjvk/sudoku_solver
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/cjvk/sudoku_solver" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcjvk%2Fsudoku_solver", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcjvk%2Fsudoku_solver'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 24d14f155d88d4b8cb62de9ef07224016915150e
[INFO] checking cjvk/sudoku_solver against master#4008bbdf34b583ce44a467043aae3703afc0a76f for pr-129249-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcjvk%2Fsudoku_solver" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/cjvk/sudoku_solver
[INFO] finished tweaking git repo https://github.com/cjvk/sudoku_solver
[INFO] tweaked toml for git repo https://github.com/cjvk/sudoku_solver written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/cjvk/sudoku_solver on toolchain 4008bbdf34b583ce44a467043aae3703afc0a76f
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4008bbdf34b583ce44a467043aae3703afc0a76f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/cjvk/sudoku_solver already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4008bbdf34b583ce44a467043aae3703afc0a76f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rand v0.5.6
[INFO] [stderr]   Downloaded rand_core v0.3.1
[INFO] [stderr]   Downloaded fuchsia-cprng v0.1.1
[INFO] [stderr]   Downloaded rand_core v0.4.2
[INFO] [stderr]   Downloaded cloudabi v0.0.3
[INFO] [stderr]   Downloaded bitflags v1.2.1
[INFO] [stderr]   Downloaded libc v0.2.68
[INFO] [stderr]   Downloaded winapi v0.3.8
[INFO] [stderr]   Downloaded winapi-i686-pc-windows-gnu v0.4.0
[INFO] [stderr]   Downloaded winapi-x86_64-pc-windows-gnu v0.4.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f
[INFO] running `Command { std: "docker" "start" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f" "/opt/rustwide/cargo-home/bin/cargo" "+4008bbdf34b583ce44a467043aae3703afc0a76f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-w" "/opt/rustwide/workdir" "--user" "0:0" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f" "/opt/rustwide/cargo-home/bin/cargo" "+4008bbdf34b583ce44a467043aae3703afc0a76f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.68
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking sudoku_solver v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/solver.rs:289:17
[INFO] [stdout]     |
[INFO] [stdout] 289 |                 'inner: while !self.queue_item_list.is_empty() {
[INFO] [stdout]     |                 ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:596:18
[INFO] [stdout]     |
[INFO] [stdout] 596 |             1 => (1..4),
[INFO] [stdout]     |                  ^    ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 596 -             1 => (1..4),
[INFO] [stdout] 596 +             1 => 1..4 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:597:18
[INFO] [stdout]     |
[INFO] [stdout] 597 |             2 => (4..7),
[INFO] [stdout]     |                  ^    ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 597 -             2 => (4..7),
[INFO] [stdout] 597 +             2 => 4..7 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:598:18
[INFO] [stdout]     |
[INFO] [stdout] 598 |             3 => (7..10),
[INFO] [stdout]     |                  ^     ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 598 -             3 => (7..10),
[INFO] [stdout] 598 +             3 => 7..10 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/solver.rs:289:17
[INFO] [stdout]     |
[INFO] [stdout] 289 |                 'inner: while !self.queue_item_list.is_empty() {
[INFO] [stdout]     |                 ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:596:18
[INFO] [stdout]     |
[INFO] [stdout] 596 |             1 => (1..4),
[INFO] [stdout]     |                  ^    ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 596 -             1 => (1..4),
[INFO] [stdout] 596 +             1 => 1..4 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:597:18
[INFO] [stdout]     |
[INFO] [stdout] 597 |             2 => (4..7),
[INFO] [stdout]     |                  ^    ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 597 -             2 => (4..7),
[INFO] [stdout] 597 +             2 => 4..7 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around match arm expression
[INFO] [stdout]    --> src/constraint.rs:598:18
[INFO] [stdout]     |
[INFO] [stdout] 598 |             3 => (7..10),
[INFO] [stdout]     |                  ^     ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 598 -             3 => (7..10),
[INFO] [stdout] 598 +             3 => 7..10 ,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]    --> src/constraint.rs:687:18
[INFO] [stdout]     |
[INFO] [stdout] 687 |         for i in (0..10) {
[INFO] [stdout]     |                  ^     ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 687 -         for i in (0..10) {
[INFO] [stdout] 687 +         for i in 0..10  {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]    --> src/constraint.rs:697:26
[INFO] [stdout]     |
[INFO] [stdout] 697 |         'outer: for i in (0..10) {
[INFO] [stdout]     |                          ^     ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 697 -         'outer: for i in (0..10) {
[INFO] [stdout] 697 +         'outer: for i in 0..10  {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]    --> src/constraint.rs:698:30
[INFO] [stdout]     |
[INFO] [stdout] 698 |             'inner: for j in (0..10) {
[INFO] [stdout]     |                              ^     ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 698 -             'inner: for j in (0..10) {
[INFO] [stdout] 698 +             'inner: for j in 0..10  {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/constraint.rs:698:13
[INFO] [stdout]     |
[INFO] [stdout] 698 |             'inner: for j in (0..10) {
[INFO] [stdout]     |             ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]    --> src/constraint.rs:977:26
[INFO] [stdout]     |
[INFO] [stdout] 977 |                 for i in (0..9) {
[INFO] [stdout]     |                          ^    ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 977 -                 for i in (0..9) {
[INFO] [stdout] 977 +                 for i in 0..9  {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]    --> src/constraint.rs:998:26
[INFO] [stdout]     |
[INFO] [stdout] 998 |                 for i in (0..9) {
[INFO] [stdout]     |                          ^    ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 998 -                 for i in (0..9) {
[INFO] [stdout] 998 +                 for i in 0..9  {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1019:26
[INFO] [stdout]      |
[INFO] [stdout] 1019 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1019 -                 for i in (0..9) {
[INFO] [stdout] 1019 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1040:26
[INFO] [stdout]      |
[INFO] [stdout] 1040 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1040 -                 for i in (0..9) {
[INFO] [stdout] 1040 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1061:26
[INFO] [stdout]      |
[INFO] [stdout] 1061 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1061 -                 for i in (0..9) {
[INFO] [stdout] 1061 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1082:26
[INFO] [stdout]      |
[INFO] [stdout] 1082 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1082 -                 for i in (0..9) {
[INFO] [stdout] 1082 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1103:26
[INFO] [stdout]      |
[INFO] [stdout] 1103 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1103 -                 for i in (0..9) {
[INFO] [stdout] 1103 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1124:26
[INFO] [stdout]      |
[INFO] [stdout] 1124 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1124 -                 for i in (0..9) {
[INFO] [stdout] 1124 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]     --> src/constraint.rs:1145:26
[INFO] [stdout]      |
[INFO] [stdout] 1145 |                 for i in (0..9) {
[INFO] [stdout]      |                          ^    ^
[INFO] [stdout]      |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1145 -                 for i in (0..9) {
[INFO] [stdout] 1145 +                 for i in 0..9  {
[INFO] [stdout]      |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `eliminate_list` is never used
[INFO] [stdout]   --> src/squares.rs:12:8
[INFO] [stdout]    |
[INFO] [stdout]  6 | pub trait Square {
[INFO] [stdout]    |           ------ method in this trait
[INFO] [stdout] ...
[INFO] [stdout] 12 |     fn eliminate_list(&mut self, arg: &Vec<usize>) -> ();
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> src/sample_puzzles.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub struct Puzzle {
[INFO] [stdout]   |            ------ field in this struct
[INFO] [stdout] 4 |     pub id: String,
[INFO] [stdout]   |         ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `remaining`
[INFO] [stdout]    --> src/squares.rs:341:17
[INFO] [stdout]     |
[INFO] [stdout] 341 |             let remaining = s.values_remaining();
[INFO] [stdout]     |                 ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_remaining`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/solver.rs:499:13
[INFO] [stdout]     |
[INFO] [stdout] 499 |         let mut s = Solver::new(get_sample_puzzle(), get_ordering());
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/solver.rs:499:13
[INFO] [stdout]     |
[INFO] [stdout] 499 |         let mut s = Solver::new(get_sample_puzzle(), get_ordering());
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `puzzle`
[INFO] [stdout]    --> src/sudoku_puzzle.rs:141:13
[INFO] [stdout]     |
[INFO] [stdout] 141 |         let puzzle = SudokuPuzzle::new(empty_puzzle());
[INFO] [stdout]     |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_puzzle`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/constraint.rs:696:13
[INFO] [stdout]     |
[INFO] [stdout] 696 |         let mut b = false;
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]    --> src/constraint.rs:696:13
[INFO] [stdout]     |
[INFO] [stdout] 696 |         let mut b = false;
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/constraint.rs:764:13
[INFO] [stdout]     |
[INFO] [stdout] 764 |         let mut constraint1 = ProcessOfElimination:: new();
[INFO] [stdout]     |             ----^^^^^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint1`
[INFO] [stdout]    --> src/constraint.rs:764:13
[INFO] [stdout]     |
[INFO] [stdout] 764 |         let mut constraint1 = ProcessOfElimination:: new();
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/constraint.rs:822:13
[INFO] [stdout]     |
[INFO] [stdout] 822 |         let mut constraint = NoBoxDuplicates::new();
[INFO] [stdout]     |             ----^^^^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint`
[INFO] [stdout]    --> src/constraint.rs:822:13
[INFO] [stdout]     |
[INFO] [stdout] 822 |         let mut constraint = NoBoxDuplicates::new();
[INFO] [stdout]     |             ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/constraint.rs:931:13
[INFO] [stdout]     |
[INFO] [stdout] 931 |         let mut constraint = NoBoxDuplicates::new();
[INFO] [stdout]     |             ----^^^^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint`
[INFO] [stdout]    --> src/constraint.rs:931:13
[INFO] [stdout]     |
[INFO] [stdout] 931 |         let mut constraint = NoBoxDuplicates::new();
[INFO] [stdout]     |             ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]     --> src/constraint.rs:1200:13
[INFO] [stdout]      |
[INFO] [stdout] 1200 |         let mut constraint = NoColumnDuplicates::new();
[INFO] [stdout]      |             ----^^^^^^^^^^
[INFO] [stdout]      |             |
[INFO] [stdout]      |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint`
[INFO] [stdout]     --> src/constraint.rs:1200:13
[INFO] [stdout]      |
[INFO] [stdout] 1200 |         let mut constraint = NoColumnDuplicates::new();
[INFO] [stdout]      |             ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]     --> src/constraint.rs:1274:13
[INFO] [stdout]      |
[INFO] [stdout] 1274 |         let mut constraint = NoRowDuplicates::new();
[INFO] [stdout]      |             ----^^^^^^^^^^
[INFO] [stdout]      |             |
[INFO] [stdout]      |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint`
[INFO] [stdout]     --> src/constraint.rs:1274:13
[INFO] [stdout]      |
[INFO] [stdout] 1274 |         let mut constraint = NoRowDuplicates::new();
[INFO] [stdout]      |             ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]     --> src/constraint.rs:1334:13
[INFO] [stdout]      |
[INFO] [stdout] 1334 |         let mut constraint = NoRowDuplicates::new();
[INFO] [stdout]      |             ----^^^^^^^^^^
[INFO] [stdout]      |             |
[INFO] [stdout]      |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `constraint`
[INFO] [stdout]     --> src/constraint.rs:1334:13
[INFO] [stdout]      |
[INFO] [stdout] 1334 |         let mut constraint = NoRowDuplicates::new();
[INFO] [stdout]      |             ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_constraint`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `foo1`
[INFO] [stdout]   --> src/test.rs:52:13
[INFO] [stdout]    |
[INFO] [stdout] 52 |         let foo1 = Foo {
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_foo1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `foo2`
[INFO] [stdout]   --> src/test.rs:59:13
[INFO] [stdout]    |
[INFO] [stdout] 59 |         let foo2 = Foo {
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_foo2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/test.rs:78:13
[INFO] [stdout]    |
[INFO] [stdout] 78 |         let mut x = 5;
[INFO] [stdout]    |             ----^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/test.rs:170:25
[INFO] [stdout]     |
[INFO] [stdout] 170 |             fn do_stuff(s: String) {}
[INFO] [stdout]     |                         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/test.rs:178:29
[INFO] [stdout]     |
[INFO] [stdout] 178 |             fn do_stuff_ref(s: &String) {}
[INFO] [stdout]     |                             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/test.rs:193:27
[INFO] [stdout]     |
[INFO] [stdout] 193 |             fn do_stuff_x(x: Foo) {}
[INFO] [stdout]     |                           ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `foo5`
[INFO] [stdout]    --> src/test.rs:258:13
[INFO] [stdout]     |
[INFO] [stdout] 258 |         let foo5 = InnerStringMutRef2{foo: &mut s5a, bar: &mut s5b};
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_foo5`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `test_no_box_duplicates` is never used
[INFO] [stdout]    --> src/constraint.rs:909:8
[INFO] [stdout]     |
[INFO] [stdout] 909 |     fn test_no_box_duplicates() {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `foo` is never read
[INFO] [stdout]  --> src/test.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     struct InnerString {
[INFO] [stdout]   |            ----------- field in this struct
[INFO] [stdout] 5 |         foo: String,
[INFO] [stdout]   |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `foo` and `bar` are never read
[INFO] [stdout]   --> src/test.rs:9:9
[INFO] [stdout]    |
[INFO] [stdout]  8 |     struct InnerStringRef<'a> {
[INFO] [stdout]    |            -------------- fields in this struct
[INFO] [stdout]  9 |         foo: &'a String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 10 |         bar: &'a String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `foo` and `bar` are never read
[INFO] [stdout]   --> src/test.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 13 |     struct InnerStringMutRef<'a> {
[INFO] [stdout]    |            ----------------- fields in this struct
[INFO] [stdout] 14 |         foo: &'a mut String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 15 |         bar: &'a mut String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `foo` and `bar` are never read
[INFO] [stdout]   --> src/test.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     struct InnerStringMutRef2<'a> {
[INFO] [stdout]    |            ------------------ fields in this struct
[INFO] [stdout] 19 |         foo: &'a mut String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 20 |         bar: &'a mut String,
[INFO] [stdout]    |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `name` is never read
[INFO] [stdout]   --> src/test.rs:35:13
[INFO] [stdout]    |
[INFO] [stdout] 34 |         struct Bar {
[INFO] [stdout]    |                --- field in this struct
[INFO] [stdout] 35 |             name: String,
[INFO] [stdout]    |             ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name` and `bar` are never read
[INFO] [stdout]   --> src/test.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 38 |         struct Foo {
[INFO] [stdout]    |                --- fields in this struct
[INFO] [stdout] 39 |             name: String,
[INFO] [stdout]    |             ^^^^
[INFO] [stdout] 40 |             bar: Bar,
[INFO] [stdout]    |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `get_name`, `set_name`, `get_bar`, and `set_bar` are never used
[INFO] [stdout]   --> src/test.rs:45:16
[INFO] [stdout]    |
[INFO] [stdout] 43 |         impl Foo {
[INFO] [stdout]    |         -------- methods in this implementation
[INFO] [stdout] 44 |             // '&' comes after '.' according to rust operator precedence
[INFO] [stdout] 45 |             fn get_name(&self) -> &String { &self.name }
[INFO] [stdout]    |                ^^^^^^^^
[INFO] [stdout] 46 |             fn set_name(&mut self, name: String) -> () { self.name = name }
[INFO] [stdout]    |                ^^^^^^^^
[INFO] [stdout] 47 |             fn get_bar(&self) -> &Bar { &self.bar }
[INFO] [stdout]    |                ^^^^^^^
[INFO] [stdout] 48 |             fn set_bar(&mut self, bar: Bar) -> () { self.bar = bar }
[INFO] [stdout]    |                ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> src/sample_puzzles.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub struct Puzzle {
[INFO] [stdout]   |            ------ field in this struct
[INFO] [stdout] 4 |     pub id: String,
[INFO] [stdout]   |         ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:775:17
[INFO] [stdout]     |
[INFO] [stdout] 775 |                 constraint1.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 775 |                 let _ = constraint1.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:776:17
[INFO] [stdout]     |
[INFO] [stdout] 776 |                 constraint2.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 776 |                 let _ = constraint2.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:777:17
[INFO] [stdout]     |
[INFO] [stdout] 777 |                 constraint3.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 777 |                 let _ = constraint3.process(&QueueItem{row:*i, column:*j}, &mut puzzle);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:839:17
[INFO] [stdout]     |
[INFO] [stdout] 839 |                 constraint.process(&QueueItem{row:i, column:j}, &mut puzzle);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 839 |                 let _ = constraint.process(&QueueItem{row:i, column:j}, &mut puzzle);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:861:21
[INFO] [stdout]     |
[INFO] [stdout] 861 |                     constraint.process(&QueueItem{row:i, column:j}, puzzle);
[INFO] [stdout]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 861 |                     let _ = constraint.process(&QueueItem{row:i, column:j}, puzzle);
[INFO] [stdout]     |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/constraint.rs:944:17
[INFO] [stdout]     |
[INFO] [stdout] 944 |                 constraint.process(&QueueItem{row:i, column:j}, &mut puzzle);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 944 |                 let _ = constraint.process(&QueueItem{row:i, column:j}, &mut puzzle);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]     --> src/constraint.rs:1210:29
[INFO] [stdout]      |
[INFO] [stdout] 1210 |             .for_each(|r| { constraint.process(&QueueItem{row:r, column:1}, &mut puzzle); });
[INFO] [stdout]      |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]      |
[INFO] [stdout] 1210 |             .for_each(|r| { let _ = constraint.process(&QueueItem{row:r, column:1}, &mut puzzle); });
[INFO] [stdout]      |                             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]     --> src/constraint.rs:1220:37
[INFO] [stdout]      |
[INFO] [stdout] 1220 |                     .for_each(|r| { constraint.process(&QueueItem{row:r, column:column}, &mut puzzle); });
[INFO] [stdout]      |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]      |
[INFO] [stdout] 1220 |                     .for_each(|r| { let _ = constraint.process(&QueueItem{row:r, column:column}, &mut puzzle); });
[INFO] [stdout]      |                                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]     --> src/constraint.rs:1284:29
[INFO] [stdout]      |
[INFO] [stdout] 1284 |             .for_each(|c| { constraint.process(&QueueItem{row:1, column:c}, &mut puzzle); });
[INFO] [stdout]      |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]      |
[INFO] [stdout] 1284 |             .for_each(|c| { let _ = constraint.process(&QueueItem{row:1, column:c}, &mut puzzle); });
[INFO] [stdout]      |                             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]     --> src/constraint.rs:1294:37
[INFO] [stdout]      |
[INFO] [stdout] 1294 |                     .for_each(|c| { constraint.process(&QueueItem{row:row, column:c}, &mut puzzle); });
[INFO] [stdout]      |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]      |
[INFO] [stdout] 1294 |                     .for_each(|c| { let _ = constraint.process(&QueueItem{row:row, column:c}, &mut puzzle); });
[INFO] [stdout]      |                                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]     --> src/constraint.rs:1337:9
[INFO] [stdout]      |
[INFO] [stdout] 1337 |         constraint.process(&QueueItem{row:1, column: 1}, &mut puzzle);
[INFO] [stdout]      |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]      |
[INFO] [stdout] 1337 |         let _ = constraint.process(&QueueItem{row:1, column: 1}, &mut puzzle);
[INFO] [stdout]      |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.59s
[INFO] running `Command { std: "docker" "inspect" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f", kill_on_drop: false }`
[INFO] [stdout] 8e085830ab0f8c518e7401806f96d2aff9b72a657a5e47a1662f78b0739a2d5f
