[INFO] crate sudoku 0.7.0 is already in cache
[INFO] extracting crate sudoku 0.7.0 into work/ex/clippy-test-run/sources/stable/reg/sudoku/0.7.0
[INFO] extracting crate sudoku 0.7.0 into work/ex/clippy-test-run/sources/stable+rustflags=-Dclippy%3A%3Ainto_iter_on_array/reg/sudoku/0.7.0
[INFO] validating manifest of sudoku-0.7.0 on toolchain stable
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of sudoku-0.7.0 on toolchain stable+rustflags=-Dclippy::into_iter_on_array
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing sudoku-0.7.0
[INFO] finished frobbing sudoku-0.7.0
[INFO] frobbed toml for sudoku-0.7.0 written to work/ex/clippy-test-run/sources/stable/reg/sudoku/0.7.0/Cargo.toml
[INFO] started frobbing sudoku-0.7.0
[INFO] finished frobbing sudoku-0.7.0
[INFO] frobbed toml for sudoku-0.7.0 written to work/ex/clippy-test-run/sources/stable+rustflags=-Dclippy%3A%3Ainto_iter_on_array/reg/sudoku/0.7.0/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+stable" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] linting sudoku-0.7.0 against stable for clippy-test-run
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/clippy-test-run/worker-5/stable:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/clippy-test-run/sources/stable/reg/sudoku/0.7.0:/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" "+stable" "clippy" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 6c0bbf3465cb9a545bb6d3df6ff5c503450d15ec64bddb63849399359360b8b6
[INFO] running `"docker" "start" "-a" "6c0bbf3465cb9a545bb6d3df6ff5c503450d15ec64bddb63849399359360b8b6"`
[INFO] [stderr]    Compiling crunchy v0.2.1
[INFO] [stderr]     Checking sudoku v0.7.0 (/opt/crater/workdir)
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/bitset.rs:257:19
[INFO] [stderr]     |
[INFO] [stderr] 257 |     Cell => u128, 0o777_777_777___777_777_777___777_777_777,
[INFO] [stderr]     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o777_777_777_777_777_777_777_777_777`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::inconsistent_digit_grouping)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: this `else { if .. }` block can be collapsed
[INFO] [stderr]    --> src/strategy/solver.rs:435:10
[INFO] [stderr]     |
[INFO] [stderr] 435 |           } else {
[INFO] [stderr]     |  ________________^
[INFO] [stderr] 436 | |             if cell_mask.is_empty() {
[INFO] [stderr] 437 | |                 return Err(Unsolvable)
[INFO] [stderr] 438 | |             }
[INFO] [stderr] 439 | |         }
[INFO] [stderr]     | |_________^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::collapsible_if)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
[INFO] [stderr] help: try
[INFO] [stderr]     |
[INFO] [stderr] 435 |         } else if cell_mask.is_empty() {
[INFO] [stderr] 436 |     return Err(Unsolvable)
[INFO] [stderr] 437 | }
[INFO] [stderr]     |
[INFO] [stderr] 
[INFO] [stderr] warning: this if statement can be collapsed
[INFO] [stderr]   --> src/strategy/strategies/hidden_subsets.rs:40:9
[INFO] [stderr]    |
[INFO] [stderr] 40 | /         if digit_set.len() == subset_size && total_poss_pos.len() == subset_size {
[INFO] [stderr] 41 | |             if on_subset(house, digit_set, total_poss_pos) {
[INFO] [stderr] 42 | |                 return true;
[INFO] [stderr] 43 | |             }
[INFO] [stderr] 44 | |         }
[INFO] [stderr]    | |_________^
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
[INFO] [stderr] help: try
[INFO] [stderr]    |
[INFO] [stderr] 40 |         if digit_set.len() == subset_size && total_poss_pos.len() == subset_size && on_subset(house, digit_set, total_poss_pos) {
[INFO] [stderr] 41 |     return true;
[INFO] [stderr] 42 | }
[INFO] [stderr]    |
[INFO] [stderr] 
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/board/positions.rs:393:21
[INFO] [stderr]     |
[INFO] [stderr] 393 |     Col  => |col| { 0o_001_001_001___001_001_001___001_001_001 << col.0 };
[INFO] [stderr]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o001_001_001_001_001_001_001_001_001`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/board/positions.rs:429:24
[INFO] [stderr]     |
[INFO] [stderr] 429 |     Stack => |stack| { 0o_007_007_007___007_007_007___007_007_007 << 3 * stack.0 };
[INFO] [stderr]     |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o007_007_007_007_007_007_007_007_007`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/bitset.rs:257:19
[INFO] [stderr]     |
[INFO] [stderr] 257 |     Cell => u128, 0o777_777_777___777_777_777___777_777_777,
[INFO] [stderr]     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o777_777_777_777_777_777_777_777_777`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::inconsistent_digit_grouping)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: this `else { if .. }` block can be collapsed
[INFO] [stderr]    --> src/strategy/solver.rs:435:10
[INFO] [stderr]     |
[INFO] [stderr] 435 |           } else {
[INFO] [stderr]     |  ________________^
[INFO] [stderr] 436 | |             if cell_mask.is_empty() {
[INFO] [stderr] 437 | |                 return Err(Unsolvable)
[INFO] [stderr] 438 | |             }
[INFO] [stderr] 439 | |         }
[INFO] [stderr]     | |_________^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::collapsible_if)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
[INFO] [stderr] help: try
[INFO] [stderr]     |
[INFO] [stderr] 435 |         } else if cell_mask.is_empty() {
[INFO] [stderr] 436 |     return Err(Unsolvable)
[INFO] [stderr] 437 | }
[INFO] [stderr]     |
[INFO] [stderr] 
[INFO] [stderr] warning: this if statement can be collapsed
[INFO] [stderr]   --> src/strategy/strategies/hidden_subsets.rs:40:9
[INFO] [stderr]    |
[INFO] [stderr] 40 | /         if digit_set.len() == subset_size && total_poss_pos.len() == subset_size {
[INFO] [stderr] 41 | |             if on_subset(house, digit_set, total_poss_pos) {
[INFO] [stderr] 42 | |                 return true;
[INFO] [stderr] 43 | |             }
[INFO] [stderr] 44 | |         }
[INFO] [stderr]    | |_________^
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
[INFO] [stderr] help: try
[INFO] [stderr]    |
[INFO] [stderr] 40 |         if digit_set.len() == subset_size && total_poss_pos.len() == subset_size && on_subset(house, digit_set, total_poss_pos) {
[INFO] [stderr] 41 |     return true;
[INFO] [stderr] 42 | }
[INFO] [stderr]    |
[INFO] [stderr] 
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/board/positions.rs:393:21
[INFO] [stderr]     |
[INFO] [stderr] 393 |     Col  => |col| { 0o_001_001_001___001_001_001___001_001_001 << col.0 };
[INFO] [stderr]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o001_001_001_001_001_001_001_001_001`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: digits grouped inconsistently by underscores
[INFO] [stderr]    --> src/board/positions.rs:429:24
[INFO] [stderr]     |
[INFO] [stderr] 429 |     Stack => |stack| { 0o_007_007_007___007_007_007___007_007_007 << 3 * stack.0 };
[INFO] [stderr]     |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider: `0o007_007_007_007_007_007_007_007_007`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#inconsistent_digit_grouping
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:553:8
[INFO] [stderr]     |
[INFO] [stderr] 553 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::len_zero)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:589:8
[INFO] [stderr]     |
[INFO] [stderr] 589 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:626:8
[INFO] [stderr]     |
[INFO] [stderr] 626 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:679:8
[INFO] [stderr]     |
[INFO] [stderr] 679 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: item `strategy::deduction::Deductions` has a public `len` method but no corresponding `is_empty` method
[INFO] [stderr]   --> src/strategy/deduction.rs:34:1
[INFO] [stderr]    |
[INFO] [stderr] 34 | / impl Deductions {
[INFO] [stderr] 35 | |     /// Returns the number of deductions.
[INFO] [stderr] 36 | |     pub fn len(&self) -> usize {
[INFO] [stderr] 37 | |         self.deductions.len()
[INFO] [stderr] ...  |
[INFO] [stderr] 52 | |     }
[INFO] [stderr] 53 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::len_without_is_empty)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `chute_line` is only used to index `line_unique_digits`.
[INFO] [stderr]   --> src/strategy/strategies/locked_candidates.rs:42:31
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for chute_line in 0..3 {
[INFO] [stderr]    |                               ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::needless_range_loop)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
[INFO] [stderr] help: consider using an iterator
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for <item> in &mut line_unique_digits {
[INFO] [stderr]    |                 ^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `chute_field` is only used to index `block_unique_digits`.
[INFO] [stderr]   --> src/strategy/strategies/locked_candidates.rs:49:32
[INFO] [stderr]    |
[INFO] [stderr] 49 |             for chute_field in 0..3 {
[INFO] [stderr]    |                                ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
[INFO] [stderr] help: consider using an iterator
[INFO] [stderr]    |
[INFO] [stderr] 49 |             for <item> in &mut block_unique_digits {
[INFO] [stderr]    |                 ^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: this argument is passed by reference, but would be more efficient if passed by value
[INFO] [stderr]    --> src/board/sudoku.rs:806:20
[INFO] [stderr]     |
[INFO] [stderr] 806 | fn num_to_opt(num: &u8) -> Option<u8> {
[INFO] [stderr]     |                    ^^^ help: consider passing by value instead: `u8`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::trivially_copy_pass_by_ref)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:553:8
[INFO] [stderr]     |
[INFO] [stderr] 553 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::len_zero)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:589:8
[INFO] [stderr]     |
[INFO] [stderr] 589 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:626:8
[INFO] [stderr]     |
[INFO] [stderr] 626 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:679:8
[INFO] [stderr]     |
[INFO] [stderr] 679 |                 if rg_eliminations.len() > 0 {
[INFO] [stderr]     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!rg_eliminations.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> src/strategy/solver.rs:879:12
[INFO] [stderr]     |
[INFO] [stderr] 879 |         if unsolved.len() != 0 {
[INFO] [stderr]     |            ^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!unsolved.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] warning: item `strategy::deduction::Deductions` has a public `len` method but no corresponding `is_empty` method
[INFO] [stderr]   --> src/strategy/deduction.rs:34:1
[INFO] [stderr]    |
[INFO] [stderr] 34 | / impl Deductions {
[INFO] [stderr] 35 | |     /// Returns the number of deductions.
[INFO] [stderr] 36 | |     pub fn len(&self) -> usize {
[INFO] [stderr] 37 | |         self.deductions.len()
[INFO] [stderr] ...  |
[INFO] [stderr] 52 | |     }
[INFO] [stderr] 53 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::len_without_is_empty)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `chute_line` is only used to index `line_unique_digits`.
[INFO] [stderr]   --> src/strategy/strategies/locked_candidates.rs:42:31
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for chute_line in 0..3 {
[INFO] [stderr]    |                               ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::needless_range_loop)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
[INFO] [stderr] help: consider using an iterator
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for <item> in &mut line_unique_digits {
[INFO] [stderr]    |                 ^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `chute_field` is only used to index `block_unique_digits`.
[INFO] [stderr]   --> src/strategy/strategies/locked_candidates.rs:49:32
[INFO] [stderr]    |
[INFO] [stderr] 49 |             for chute_field in 0..3 {
[INFO] [stderr]    |                                ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
[INFO] [stderr] help: consider using an iterator
[INFO] [stderr]    |
[INFO] [stderr] 49 |             for <item> in &mut block_unique_digits {
[INFO] [stderr]    |                 ^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: this argument is passed by reference, but would be more efficient if passed by value
[INFO] [stderr]    --> src/board/sudoku.rs:806:20
[INFO] [stderr]     |
[INFO] [stderr] 806 | fn num_to_opt(num: &u8) -> Option<u8> {
[INFO] [stderr]     |                    ^^^ help: consider passing by value instead: `u8`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::trivially_copy_pass_by_ref)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref
[INFO] [stderr] 
[INFO] [stderr] warning: casting u8 to u32 may become silently lossy if types change
[INFO] [stderr]   --> examples/project_euler.rs:20:65
[INFO] [stderr]    |
[INFO] [stderr] 20 |         sum += array[..3].iter().fold(0, |acc, &num| acc * 10 + num as u32);
[INFO] [stderr]    |                                                                 ^^^^^^^^^^ help: try: `u32::from(num)`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::cast_lossless)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> benches/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(test)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `sudoku`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]    --> tests/lib.rs:289:8
[INFO] [stderr]     |
[INFO] [stderr] 289 |     if duplicates.len() > 0 {
[INFO] [stderr]     |        ^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!duplicates.is_empty()`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(clippy::len_zero)] on by default
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stderr] 
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "6c0bbf3465cb9a545bb6d3df6ff5c503450d15ec64bddb63849399359360b8b6"`
[INFO] running `"docker" "rm" "-f" "6c0bbf3465cb9a545bb6d3df6ff5c503450d15ec64bddb63849399359360b8b6"`
[INFO] [stdout] 6c0bbf3465cb9a545bb6d3df6ff5c503450d15ec64bddb63849399359360b8b6