[INFO] updating cached repository mrbech/aoc2018
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/mrbech/aoc2018
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/mrbech/aoc2018" "work/ex/clippy-test-run/sources/stable/gh/mrbech/aoc2018"`
[INFO] [stderr] Cloning into 'work/ex/clippy-test-run/sources/stable/gh/mrbech/aoc2018'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/mrbech/aoc2018" "work/ex/clippy-test-run/sources/stable+rustflags=-Dclippy%3A%3Ainto_iter_on_array/gh/mrbech/aoc2018"`
[INFO] [stderr] Cloning into 'work/ex/clippy-test-run/sources/stable+rustflags=-Dclippy%3A%3Ainto_iter_on_array/gh/mrbech/aoc2018'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] ea974b7397dfe86e74b63e509ffdf37fd0f6be8a
[INFO] sha for GitHub repo mrbech/aoc2018: ea974b7397dfe86e74b63e509ffdf37fd0f6be8a
[INFO] validating manifest of mrbech/aoc2018 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 mrbech/aoc2018 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 mrbech/aoc2018
[INFO] finished frobbing mrbech/aoc2018
[INFO] frobbed toml for mrbech/aoc2018 written to work/ex/clippy-test-run/sources/stable/gh/mrbech/aoc2018/Cargo.toml
[INFO] started frobbing mrbech/aoc2018
[INFO] finished frobbing mrbech/aoc2018
[INFO] frobbed toml for mrbech/aoc2018 written to work/ex/clippy-test-run/sources/stable+rustflags=-Dclippy%3A%3Ainto_iter_on_array/gh/mrbech/aoc2018/Cargo.toml
[INFO] crate mrbech/aoc2018 has a lockfile. skipping
[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 mrbech/aoc2018 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/gh/mrbech/aoc2018:/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] 89f311c39ffecc64c0364f2424ef0c9289e894dbe917589a3ff09ac7a3978cce
[INFO] running `"docker" "start" "-a" "89f311c39ffecc64c0364f2424ef0c9289e894dbe917589a3ff09ac7a3978cce"`
[INFO] [stderr]     Checking aoc2018 v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: redundant field names in struct initialization
[INFO] [stderr]   --> src/day4/mod.rs:92:21
[INFO] [stderr]    |
[INFO] [stderr] 92 |                     asleep: asleep
[INFO] [stderr]    |                     ^^^^^^^^^^^^^^ help: replace it with: `asleep`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::redundant_field_names)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names
[INFO] [stderr] 
[INFO] [stderr] warning: redundant field names in struct initialization
[INFO] [stderr]   --> src/day4/mod.rs:92:21
[INFO] [stderr]    |
[INFO] [stderr] 92 |                     asleep: asleep
[INFO] [stderr]    |                     ^^^^^^^^^^^^^^ help: replace it with: `asleep`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::redundant_field_names)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names
[INFO] [stderr] 
[INFO] [stderr] warning: manual implementation of an assign operation
[INFO] [stderr]   --> src/day1/mod.rs:14:13
[INFO] [stderr]    |
[INFO] [stderr] 14 |             *f = *f + c;
[INFO] [stderr]    |             ^^^^^^^^^^^ help: replace it with: `*f += c`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::assign_op_pattern)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assign_op_pattern
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]  --> src/day2/mod.rs:5:27
[INFO] [stderr]   |
[INFO] [stderr] 5 |     fn char_occurences(s: &String) -> HashMap<char, i32> {
[INFO] [stderr]   |                           ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(clippy::ptr_arg)] on by default
[INFO] [stderr]   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: manual implementation of an assign operation
[INFO] [stderr]   --> src/day1/mod.rs:14:13
[INFO] [stderr]    |
[INFO] [stderr] 14 |             *f = *f + c;
[INFO] [stderr]    |             ^^^^^^^^^^^ help: replace it with: `*f += c`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::assign_op_pattern)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assign_op_pattern
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day2/mod.rs:32:32
[INFO] [stderr]    |
[INFO] [stderr] 32 |     fn find_similar_string(s1: &String, s2: &String) -> String {
[INFO] [stderr]    |                                ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day2/mod.rs:32:45
[INFO] [stderr]    |
[INFO] [stderr] 32 |     fn find_similar_string(s1: &String, s2: &String) -> String {
[INFO] [stderr]    |                                             ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]  --> src/day2/mod.rs:5:27
[INFO] [stderr]   |
[INFO] [stderr] 5 |     fn char_occurences(s: &String) -> HashMap<char, i32> {
[INFO] [stderr]   |                           ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(clippy::ptr_arg)] on by default
[INFO] [stderr]   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day2/mod.rs:32:32
[INFO] [stderr]    |
[INFO] [stderr] 32 |     fn find_similar_string(s1: &String, s2: &String) -> String {
[INFO] [stderr]    |                                ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day2/mod.rs:32:45
[INFO] [stderr]    |
[INFO] [stderr] 32 |     fn find_similar_string(s1: &String, s2: &String) -> String {
[INFO] [stderr]    |                                             ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: manual implementation of an assign operation
[INFO] [stderr]   --> src/day3/mod.rs:15:21
[INFO] [stderr]    |
[INFO] [stderr] 15 |                     fabrics[x][y] = fabrics[x][y] + 1
[INFO] [stderr]    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `fabrics[x][y] += 1`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assign_op_pattern
[INFO] [stderr] 
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]   --> src/day3/mod.rs:21:14
[INFO] [stderr]    |
[INFO] [stderr] 21 |             .into_iter()
[INFO] [stderr]    |              ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::into_iter_on_ref)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]   --> src/day3/mod.rs:22:24
[INFO] [stderr]    |
[INFO] [stderr] 22 |             .map(|r| r.into_iter().filter(|r| **r > 1).count() as i32)
[INFO] [stderr]    |                        ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: manual implementation of an assign operation
[INFO] [stderr]   --> src/day3/mod.rs:15:21
[INFO] [stderr]    |
[INFO] [stderr] 15 |                     fabrics[x][y] = fabrics[x][y] + 1
[INFO] [stderr]    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `fabrics[x][y] += 1`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assign_op_pattern
[INFO] [stderr] 
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]   --> src/day3/mod.rs:21:14
[INFO] [stderr]    |
[INFO] [stderr] 21 |             .into_iter()
[INFO] [stderr]    |              ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::into_iter_on_ref)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]   --> src/day3/mod.rs:22:24
[INFO] [stderr]    |
[INFO] [stderr] 22 |             .map(|r| r.into_iter().filter(|r| **r > 1).count() as i32)
[INFO] [stderr]    |                        ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `i` is used to index `minutes`
[INFO] [stderr]   --> src/day4/mod.rs:19:22
[INFO] [stderr]    |
[INFO] [stderr] 19 |             for i in 0..59 {
[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] 19 |             for (i, <item>) in minutes.iter_mut().enumerate().take(59) {
[INFO] [stderr]    |                 ^^^^^^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `i` is used to index `minutes_asleep`
[INFO] [stderr]   --> src/day4/mod.rs:42:22
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for i in 0..59 {
[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] 42 |             for (i, <item>) in minutes_asleep.iter_mut().enumerate().take(59) {
[INFO] [stderr]    |                 ^^^^^^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `i` is used to index `minutes`
[INFO] [stderr]   --> src/day4/mod.rs:19:22
[INFO] [stderr]    |
[INFO] [stderr] 19 |             for i in 0..59 {
[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] 19 |             for (i, <item>) in minutes.iter_mut().enumerate().take(59) {
[INFO] [stderr]    |                 ^^^^^^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `i` is used to index `minutes_asleep`
[INFO] [stderr]   --> src/day4/mod.rs:42:22
[INFO] [stderr]    |
[INFO] [stderr] 42 |             for i in 0..59 {
[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] 42 |             for (i, <item>) in minutes_asleep.iter_mut().enumerate().take(59) {
[INFO] [stderr]    |                 ^^^^^^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the loop variable `i` is only used to index `asleep`.
[INFO] [stderr]   --> src/day4/mod.rs:83:38
[INFO] [stderr]    |
[INFO] [stderr] 83 |                             for i in s..e {
[INFO] [stderr]    |                                      ^^^^
[INFO] [stderr]    |
[INFO] [stderr] warning: the loop variable `i` is only used to index `asleep`.
[INFO] [stderr]   --> src/day4/mod.rs:83:38
[INFO] [stderr]    |
[INFO] [stderr] 83 |                             for i in s..e {
[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] 83 |                             for <item> in asleep.iter_mut().take(e).skip(s) {
[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] 83 |                             for <item> in asleep.iter_mut().take(e).skip(s) {
[INFO] [stderr]    |                                 ^^^^^^    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]    --> src/day4/mod.rs:129:21
[INFO] [stderr]     |
[INFO] [stderr] 129 |         self.asleep.into_iter().filter(|a| **a).count() as i32
[INFO] [stderr]     |                     ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr] warning: this .into_iter() call is equivalent to .iter() and will not move the slice
[INFO] [stderr]    --> src/day4/mod.rs:129:21
[INFO] [stderr]     |
[INFO] [stderr] 129 |         self.asleep.into_iter().filter(|a| **a).count() as i32
[INFO] [stderr]     |                     ^^^^^^^^^ help: call directly: `iter`
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day5/mod.rs:35:27
[INFO] [stderr]    |
[INFO] [stderr] 35 | fn react_polymer(polymer: &String) -> String {
[INFO] [stderr]    |                           ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr]     |
[INFO] [stderr]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&String` instead of `&str` involves a new object where a slice will do.
[INFO] [stderr]   --> src/day5/mod.rs:35:27
[INFO] [stderr]    |
[INFO] [stderr] 35 | fn react_polymer(polymer: &String) -> String {
[INFO] [stderr]    |                           ^^^^^^^ help: change this to: `&str`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices.
[INFO] [stderr]   --> src/day7/mod.rs:62:77
[INFO] [stderr]    |
[INFO] [stderr] 62 | fn find_can_be_completed(steps: &HashMap<char, Vec<char>>, completed_steps: &Vec<char>) -> Option<Vec<char>> {
[INFO] [stderr]    |                                                                             ^^^^^^^^^^ help: change this to: `&[char]`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: using `clone` on a `Copy` type
[INFO] [stderr]   --> src/day7/mod.rs:65:26
[INFO] [stderr]    |
[INFO] [stderr] 65 |         .map(|(step, _)| step.clone())
[INFO] [stderr]    |                          ^^^^^^^^^^^^ help: try dereferencing it: `*step`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::clone_on_copy)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#clone_on_copy
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]   --> src/day7/mod.rs:67:8
[INFO] [stderr]    |
[INFO] [stderr] 67 |     if result.len() > 0 { Some(result) } else { None }
[INFO] [stderr]    |        ^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!result.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: use of `or_insert` followed by a function call
[INFO] [stderr]   --> src/day7/mod.rs:91:30
[INFO] [stderr]    |
[INFO] [stderr] 91 |         result.entry(before).or_insert(Vec::new());
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::or_fun_call)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call
[INFO] [stderr] 
[INFO] [stderr] warning: use of `or_insert` followed by a function call
[INFO] [stderr]   --> src/day7/mod.rs:93:42
[INFO] [stderr]    |
[INFO] [stderr] 93 |         let befores = result.entry(step).or_insert(Vec::new());
[INFO] [stderr]    |                                          ^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call
[INFO] [stderr] 
[INFO] [stderr] warning: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices.
[INFO] [stderr]   --> src/day7/mod.rs:62:77
[INFO] [stderr]    |
[INFO] [stderr] 62 | fn find_can_be_completed(steps: &HashMap<char, Vec<char>>, completed_steps: &Vec<char>) -> Option<Vec<char>> {
[INFO] [stderr]    |                                                                             ^^^^^^^^^^ help: change this to: `&[char]`
[INFO] [stderr]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
[INFO] [stderr] 
[INFO] [stderr] warning: using `clone` on a `Copy` type
[INFO] [stderr]   --> src/day7/mod.rs:65:26
[INFO] [stderr]    |
[INFO] [stderr] 65 |         .map(|(step, _)| step.clone())
[INFO] [stderr]    |                          ^^^^^^^^^^^^ help: try dereferencing it: `*step`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::clone_on_copy)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#clone_on_copy
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]   --> src/day7/mod.rs:67:8
[INFO] [stderr]    |
[INFO] [stderr] 67 |     if result.len() > 0 { Some(result) } else { None }
[INFO] [stderr]    |        ^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `!result.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: use of `or_insert` followed by a function call
[INFO] [stderr]   --> src/day7/mod.rs:91:30
[INFO] [stderr]    |
[INFO] [stderr] 91 |         result.entry(before).or_insert(Vec::new());
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(clippy::or_fun_call)] on by default
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call
[INFO] [stderr] 
[INFO] [stderr] warning: use of `or_insert` followed by a function call
[INFO] [stderr]   --> src/day7/mod.rs:93:42
[INFO] [stderr]    |
[INFO] [stderr] 93 |         let befores = result.entry(step).or_insert(Vec::new());
[INFO] [stderr]    |                                          ^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]   --> src/day8/mod.rs:22:12
[INFO] [stderr]    |
[INFO] [stderr] 22 |         if n.children.len() == 0 {
[INFO] [stderr]    |            ^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `n.children.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]    |
[INFO] [stderr]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#or_fun_call
[INFO] [stderr] 
[INFO] [stderr] warning: length comparison to zero
[INFO] [stderr]   --> src/day8/mod.rs:22:12
[INFO] [stderr]    |
[INFO] [stderr] 22 |         if n.children.len() == 0 {
[INFO] [stderr]    |            ^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `n.children.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]     Finished dev [unoptimized + debuginfo] target(s) in 1.88s
[INFO] running `"docker" "inspect" "89f311c39ffecc64c0364f2424ef0c9289e894dbe917589a3ff09ac7a3978cce"`
[INFO] running `"docker" "rm" "-f" "89f311c39ffecc64c0364f2424ef0c9289e894dbe917589a3ff09ac7a3978cce"`
[INFO] [stdout] 89f311c39ffecc64c0364f2424ef0c9289e894dbe917589a3ff09ac7a3978cce