Dec 19 20:34:08.067 INFO checking ammongit/markov-music against master#d99a320cba42f661aebfa1293b7b2ec3603dda75 for pr-56955
Dec 19 20:34:08.067 INFO running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-56955/worker-0/master#d99a320cba42f661aebfa1293b7b2ec3603dda75:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/pr-56955/sources/master#d99a320cba42f661aebfa1293b7b2ec3603dda75/gh/ammongit/markov-music:/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" "+d99a320cba42f661aebfa1293b7b2ec3603dda75-alt" "check" "--frozen" "--all" "--all-targets"`
Dec 19 20:34:08.474 INFO [stdout] b5083172a6a9d19c4e22cc139ae2df87492e15b1affb3ad35ea51346aae0367e
Dec 19 20:34:08.478 INFO running `"docker" "start" "-a" "b5083172a6a9d19c4e22cc139ae2df87492e15b1affb3ad35ea51346aae0367e"`
Dec 19 20:34:09.920 INFO [stderr]     Checking term_size v0.3.0
Dec 19 20:34:09.920 INFO [stderr]     Checking atty v0.2.2
Dec 19 20:34:09.920 INFO [stderr]     Checking thread-id v3.2.0
Dec 19 20:34:09.932 INFO [stderr]     Checking mpd v0.0.12
Dec 19 20:34:09.932 INFO [stderr]    Compiling serde_derive_internals v0.19.0
Dec 19 20:34:09.932 INFO [stderr]    Compiling diesel_derives v1.1.0
Dec 19 20:34:10.469 INFO [stderr]     Checking simple-logging v2.0.1
Dec 19 20:34:10.801 INFO [stderr]     Checking textwrap v0.7.0
Dec 19 20:34:11.344 INFO [stderr]     Checking clap v2.26.0
Dec 19 20:34:16.455 INFO [stderr]    Compiling serde_derive v1.0.27
Dec 19 20:34:16.661 INFO [stderr]     Checking diesel v1.1.1
Dec 19 20:34:22.780 INFO [stderr]     Checking serde v1.0.11
Dec 19 20:34:31.336 INFO [stderr]     Checking toml v0.4.4
Dec 19 20:34:35.259 INFO [stderr]     Checking markov-music v0.1.0 (/opt/crater/workdir)
Dec 19 20:34:36.840 INFO [stderr] warning: use of deprecated item 'std::env::home_dir': This function's behavior is unexpected and probably not what you want. Consider using the home_dir function from https://crates.io/crates/dirs instead.
Dec 19 20:34:36.840 INFO [stderr]   --> src/utils.rs:25:40
Dec 19 20:34:36.840 INFO [stderr]    |
Dec 19 20:34:36.840 INFO [stderr] 25 |     pub static ref HOME_DIR: PathBuf = env::home_dir().expect("Unable to get home directory");
Dec 19 20:34:36.840 INFO [stderr]    |                                        ^^^^^^^^^^^^^
Dec 19 20:34:36.840 INFO [stderr]    |
Dec 19 20:34:36.840 INFO [stderr]    = note: #[warn(deprecated)] on by default
Dec 19 20:34:36.840 INFO [stderr] 
Dec 19 20:34:37.170 INFO [stderr] warning: use of deprecated item 'std::env::home_dir': This function's behavior is unexpected and probably not what you want. Consider using the home_dir function from https://crates.io/crates/dirs instead.
Dec 19 20:34:37.170 INFO [stderr]   --> src/utils.rs:25:40
Dec 19 20:34:37.170 INFO [stderr]    |
Dec 19 20:34:37.170 INFO [stderr] 25 |     pub static ref HOME_DIR: PathBuf = env::home_dir().expect("Unable to get home directory");
Dec 19 20:34:37.170 INFO [stderr]    |                                        ^^^^^^^^^^^^^
Dec 19 20:34:37.170 INFO [stderr]    |
Dec 19 20:34:37.170 INFO [stderr]    = note: #[warn(deprecated)] on by default
Dec 19 20:34:37.170 INFO [stderr] 
Dec 19 20:34:37.560 INFO [stderr] warning: function is never used: `random_key`
Dec 19 20:34:37.560 INFO [stderr]   --> src/choose.rs:29:1
Dec 19 20:34:37.560 INFO [stderr]    |
Dec 19 20:34:37.560 INFO [stderr] 29 | pub fn random_key<'a, K: Eq + Hash, V>(map: &'a HashMap<K, V>, rng: &mut Rng) -> Option<&'a K> {
Dec 19 20:34:37.560 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.560 INFO [stderr]    |
Dec 19 20:34:37.560 INFO [stderr]    = note: #[warn(dead_code)] on by default
Dec 19 20:34:37.560 INFO [stderr] 
Dec 19 20:34:37.560 INFO [stderr] warning: function is never used: `roulette_wheel`
Dec 19 20:34:37.560 INFO [stderr]   --> src/choose.rs:34:1
Dec 19 20:34:37.560 INFO [stderr]    |
Dec 19 20:34:37.560 INFO [stderr] 34 | pub fn roulette_wheel<'a, K: Eq + Hash>(map: &'a HashMap<K, f32>, rng: &mut Rng) -> Option<&'a K> {
Dec 19 20:34:37.560 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.560 INFO [stderr] 
Dec 19 20:34:37.560 INFO [stderr] warning: method is never used: `modify_weight`
Dec 19 20:34:37.560 INFO [stderr]   --> src/markov.rs:47:5
Dec 19 20:34:37.560 INFO [stderr]    |
Dec 19 20:34:37.560 INFO [stderr] 47 |     pub fn modify_weight(&mut self, prev: T, next: T, diff: f32) {
Dec 19 20:34:37.560 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.560 INFO [stderr] 
Dec 19 20:34:37.560 INFO [stderr] warning: method is never used: `clear`
Dec 19 20:34:37.560 INFO [stderr]   --> src/markov.rs:55:5
Dec 19 20:34:37.560 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 55 | /     pub fn clear<U>(&mut self, item: &U)
Dec 19 20:34:37.561 INFO [stderr] 56 | |     where U: Borrow<T>,
Dec 19 20:34:37.561 INFO [stderr] 57 | |           U: ?Sized,
Dec 19 20:34:37.561 INFO [stderr] 58 | |     {
Dec 19 20:34:37.561 INFO [stderr] ...  |
Dec 19 20:34:37.561 INFO [stderr] 61 | |         }
Dec 19 20:34:37.561 INFO [stderr] 62 | |     }
Dec 19 20:34:37.561 INFO [stderr]    | |_____^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: method is never used: `start`
Dec 19 20:34:37.561 INFO [stderr]   --> src/markov.rs:64:5
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 64 |     pub fn start(&self, rng: &mut Rng) -> Option<&T> {
Dec 19 20:34:37.561 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: method is never used: `next`
Dec 19 20:34:37.561 INFO [stderr]   --> src/markov.rs:68:5
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 68 | /     pub fn next<U>(&self, current: &U, rng: &mut Rng) -> Option<&T>
Dec 19 20:34:37.561 INFO [stderr] 69 | |     where U: Borrow<T>,
Dec 19 20:34:37.561 INFO [stderr] 70 | |           U: ?Sized,
Dec 19 20:34:37.561 INFO [stderr] 71 | |     {
Dec 19 20:34:37.561 INFO [stderr] ...  |
Dec 19 20:34:37.561 INFO [stderr] 75 | |         }
Dec 19 20:34:37.561 INFO [stderr] 76 | |     }
Dec 19 20:34:37.561 INFO [stderr]    | |_____^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: method is never used: `possible_next`
Dec 19 20:34:37.561 INFO [stderr]   --> src/markov.rs:78:5
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 78 | /     pub fn possible_next<U>(&self, current: &U) -> Option<&HashMap<T, f32>>
Dec 19 20:34:37.561 INFO [stderr] 79 | |     where U: Borrow<T>,
Dec 19 20:34:37.561 INFO [stderr] 80 | |           U: ?Sized,
Dec 19 20:34:37.561 INFO [stderr] 81 | |     {
Dec 19 20:34:37.561 INFO [stderr] 82 | |         self.assocs.get(current.borrow())
Dec 19 20:34:37.561 INFO [stderr] 83 | |     }
Dec 19 20:34:37.561 INFO [stderr]    | |_____^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: function is never used: `split_cmd`
Dec 19 20:34:37.561 INFO [stderr]   --> src/socket.rs:28:1
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 28 | fn split_cmd(command: &mut str) -> (&mut str, &mut str) {
Dec 19 20:34:37.561 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: struct is never constructed: `SocketServer`
Dec 19 20:34:37.561 INFO [stderr]   --> src/socket.rs:36:1
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 36 | pub struct SocketServer {
Dec 19 20:34:37.561 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.561 INFO [stderr] 
Dec 19 20:34:37.561 INFO [stderr] warning: method is never used: `bind`
Dec 19 20:34:37.561 INFO [stderr]   --> src/socket.rs:41:5
Dec 19 20:34:37.561 INFO [stderr]    |
Dec 19 20:34:37.561 INFO [stderr] 41 |     pub fn bind(config: &DaemonConfig) -> Result<Self> {
Dec 19 20:34:37.561 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.568 INFO [stderr] 
Dec 19 20:34:37.568 INFO [stderr] warning: method is never used: `wait`
Dec 19 20:34:37.568 INFO [stderr]   --> src/socket.rs:47:5
Dec 19 20:34:37.568 INFO [stderr]    |
Dec 19 20:34:37.568 INFO [stderr] 47 |     pub fn wait(&self) -> Result<()> {
Dec 19 20:34:37.568 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.568 INFO [stderr] 
Dec 19 20:34:37.568 INFO [stderr] warning: method is never used: `respond`
Dec 19 20:34:37.568 INFO [stderr]   --> src/socket.rs:58:5
Dec 19 20:34:37.568 INFO [stderr]    |
Dec 19 20:34:37.568 INFO [stderr] 58 |     fn respond(&self, command: &mut str) -> Result<&'static str> {
Dec 19 20:34:37.568 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.568 INFO [stderr] 
Dec 19 20:34:37.568 INFO [stderr] warning: method is never used: `set_recommend`
Dec 19 20:34:37.568 INFO [stderr]   --> src/socket.rs:72:5
Dec 19 20:34:37.568 INFO [stderr]    |
Dec 19 20:34:37.568 INFO [stderr] 72 |     fn set_recommend(&self, arg: &mut str) -> &'static str {
Dec 19 20:34:37.568 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.568 INFO [stderr] 
Dec 19 20:34:37.568 INFO [stderr] warning: function is never used: `empty_mut_str`
Dec 19 20:34:37.568 INFO [stderr]   --> src/utils.rs:29:1
Dec 19 20:34:37.568 INFO [stderr]    |
Dec 19 20:34:37.568 INFO [stderr] 29 | pub fn empty_mut_str() -> &'static mut str {
Dec 19 20:34:37.568 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.568 INFO [stderr] 
Dec 19 20:34:37.569 INFO [stderr] warning: function is never used: `sigmoid`
Dec 19 20:34:37.569 INFO [stderr]   --> src/utils.rs:34:1
Dec 19 20:34:37.569 INFO [stderr]    |
Dec 19 20:34:37.569 INFO [stderr] 34 | pub fn sigmoid(n: f32) -> f32 {
Dec 19 20:34:37.569 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.569 INFO [stderr] 
Dec 19 20:34:37.924 INFO [stderr] warning: function is never used: `random_key`
Dec 19 20:34:37.924 INFO [stderr]   --> src/choose.rs:29:1
Dec 19 20:34:37.924 INFO [stderr]    |
Dec 19 20:34:37.924 INFO [stderr] 29 | pub fn random_key<'a, K: Eq + Hash, V>(map: &'a HashMap<K, V>, rng: &mut Rng) -> Option<&'a K> {
Dec 19 20:34:37.924 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.924 INFO [stderr]    |
Dec 19 20:34:37.924 INFO [stderr]    = note: #[warn(dead_code)] on by default
Dec 19 20:34:37.924 INFO [stderr] 
Dec 19 20:34:37.924 INFO [stderr] warning: function is never used: `roulette_wheel`
Dec 19 20:34:37.924 INFO [stderr]   --> src/choose.rs:34:1
Dec 19 20:34:37.924 INFO [stderr]    |
Dec 19 20:34:37.924 INFO [stderr] 34 | pub fn roulette_wheel<'a, K: Eq + Hash>(map: &'a HashMap<K, f32>, rng: &mut Rng) -> Option<&'a K> {
Dec 19 20:34:37.924 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.924 INFO [stderr] 
Dec 19 20:34:37.924 INFO [stderr] warning: method is never used: `modify_weight`
Dec 19 20:34:37.924 INFO [stderr]   --> src/markov.rs:47:5
Dec 19 20:34:37.924 INFO [stderr]    |
Dec 19 20:34:37.924 INFO [stderr] 47 |     pub fn modify_weight(&mut self, prev: T, next: T, diff: f32) {
Dec 19 20:34:37.924 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.924 INFO [stderr] 
Dec 19 20:34:37.924 INFO [stderr] warning: method is never used: `clear`
Dec 19 20:34:37.924 INFO [stderr]   --> src/markov.rs:55:5
Dec 19 20:34:37.924 INFO [stderr]    |
Dec 19 20:34:37.924 INFO [stderr] 55 | /     pub fn clear<U>(&mut self, item: &U)
Dec 19 20:34:37.924 INFO [stderr] 56 | |     where U: Borrow<T>,
Dec 19 20:34:37.924 INFO [stderr] 57 | |           U: ?Sized,
Dec 19 20:34:37.924 INFO [stderr] 58 | |     {
Dec 19 20:34:37.924 INFO [stderr] ...  |
Dec 19 20:34:37.924 INFO [stderr] 61 | |         }
Dec 19 20:34:37.924 INFO [stderr] 62 | |     }
Dec 19 20:34:37.924 INFO [stderr]    | |_____^
Dec 19 20:34:37.924 INFO [stderr] 
Dec 19 20:34:37.925 INFO [stderr] warning: method is never used: `start`
Dec 19 20:34:37.925 INFO [stderr]   --> src/markov.rs:64:5
Dec 19 20:34:37.925 INFO [stderr]    |
Dec 19 20:34:37.925 INFO [stderr] 64 |     pub fn start(&self, rng: &mut Rng) -> Option<&T> {
Dec 19 20:34:37.925 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.925 INFO [stderr] 
Dec 19 20:34:37.925 INFO [stderr] warning: method is never used: `next`
Dec 19 20:34:37.925 INFO [stderr]   --> src/markov.rs:68:5
Dec 19 20:34:37.925 INFO [stderr]    |
Dec 19 20:34:37.925 INFO [stderr] 68 | /     pub fn next<U>(&self, current: &U, rng: &mut Rng) -> Option<&T>
Dec 19 20:34:37.925 INFO [stderr] 69 | |     where U: Borrow<T>,
Dec 19 20:34:37.925 INFO [stderr] 70 | |           U: ?Sized,
Dec 19 20:34:37.925 INFO [stderr] 71 | |     {
Dec 19 20:34:37.925 INFO [stderr] ...  |
Dec 19 20:34:37.925 INFO [stderr] 75 | |         }
Dec 19 20:34:37.925 INFO [stderr] 76 | |     }
Dec 19 20:34:37.925 INFO [stderr]    | |_____^
Dec 19 20:34:37.925 INFO [stderr] 
Dec 19 20:34:37.925 INFO [stderr] warning: method is never used: `possible_next`
Dec 19 20:34:37.925 INFO [stderr]   --> src/markov.rs:78:5
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 78 | /     pub fn possible_next<U>(&self, current: &U) -> Option<&HashMap<T, f32>>
Dec 19 20:34:37.926 INFO [stderr] 79 | |     where U: Borrow<T>,
Dec 19 20:34:37.926 INFO [stderr] 80 | |           U: ?Sized,
Dec 19 20:34:37.926 INFO [stderr] 81 | |     {
Dec 19 20:34:37.926 INFO [stderr] 82 | |         self.assocs.get(current.borrow())
Dec 19 20:34:37.926 INFO [stderr] 83 | |     }
Dec 19 20:34:37.926 INFO [stderr]    | |_____^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: function is never used: `split_cmd`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:28:1
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 28 | fn split_cmd(command: &mut str) -> (&mut str, &mut str) {
Dec 19 20:34:37.926 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: struct is never constructed: `SocketServer`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:36:1
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 36 | pub struct SocketServer {
Dec 19 20:34:37.926 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: method is never used: `bind`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:41:5
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 41 |     pub fn bind(config: &DaemonConfig) -> Result<Self> {
Dec 19 20:34:37.926 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: method is never used: `wait`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:47:5
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 47 |     pub fn wait(&self) -> Result<()> {
Dec 19 20:34:37.926 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: method is never used: `respond`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:58:5
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 58 |     fn respond(&self, command: &mut str) -> Result<&'static str> {
Dec 19 20:34:37.926 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: method is never used: `set_recommend`
Dec 19 20:34:37.926 INFO [stderr]   --> src/socket.rs:72:5
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 72 |     fn set_recommend(&self, arg: &mut str) -> &'static str {
Dec 19 20:34:37.926 INFO [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: function is never used: `empty_mut_str`
Dec 19 20:34:37.926 INFO [stderr]   --> src/utils.rs:29:1
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 29 | pub fn empty_mut_str() -> &'static mut str {
Dec 19 20:34:37.926 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.926 INFO [stderr] warning: function is never used: `sigmoid`
Dec 19 20:34:37.926 INFO [stderr]   --> src/utils.rs:34:1
Dec 19 20:34:37.926 INFO [stderr]    |
Dec 19 20:34:37.926 INFO [stderr] 34 | pub fn sigmoid(n: f32) -> f32 {
Dec 19 20:34:37.926 INFO [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 19 20:34:37.926 INFO [stderr] 
Dec 19 20:34:37.984 INFO [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 28.19s
Dec 19 20:34:38.819 INFO running `"docker" "inspect" "b5083172a6a9d19c4e22cc139ae2df87492e15b1affb3ad35ea51346aae0367e"`
Dec 19 20:34:39.150 INFO running `"docker" "rm" "-f" "b5083172a6a9d19c4e22cc139ae2df87492e15b1affb3ad35ea51346aae0367e"`
Dec 19 20:34:39.532 INFO [stdout] b5083172a6a9d19c4e22cc139ae2df87492e15b1affb3ad35ea51346aae0367e