[INFO] updating cached repository ICimpoes/rusty-train
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/ICimpoes/rusty-train
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/ICimpoes/rusty-train" "work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ICimpoes/rusty-train"`
[INFO] [stderr] Cloning into 'work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ICimpoes/rusty-train'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/ICimpoes/rusty-train" "work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ICimpoes/rusty-train"`
[INFO] [stderr] Cloning into 'work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ICimpoes/rusty-train'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f5849823762ca3e361642003d886bc612bb14d8c
[INFO] sha for GitHub repo ICimpoes/rusty-train: f5849823762ca3e361642003d886bc612bb14d8c
[INFO] validating manifest of ICimpoes/rusty-train on toolchain master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of ICimpoes/rusty-train on toolchain try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing ICimpoes/rusty-train
[INFO] finished frobbing ICimpoes/rusty-train
[INFO] frobbed toml for ICimpoes/rusty-train written to work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ICimpoes/rusty-train/Cargo.toml
[INFO] started frobbing ICimpoes/rusty-train
[INFO] finished frobbing ICimpoes/rusty-train
[INFO] frobbed toml for ICimpoes/rusty-train written to work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ICimpoes/rusty-train/Cargo.toml
[INFO] crate ICimpoes/rusty-train already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking ICimpoes/rusty-train against try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b for pr-59199
[INFO] running `"docker" "create" "-v" "/mnt/crater-raid/crater/work/local/target-dirs/pr-59199/worker-3/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b:/opt/crater/target:rw,Z" "-v" "/mnt/crater-raid/crater/work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ICimpoes/rusty-train:/opt/crater/workdir:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/crater-raid/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" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] f8cabf72f35cfa047e2623c3a81447510660fb2a7666751d6488bffaa59bef31
[INFO] running `"docker" "start" "-a" "f8cabf72f35cfa047e2623c3a81447510660fb2a7666751d6488bffaa59bef31"`
[INFO] [stderr]     Checking rusty-train v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: function is never used: `middle_function`
[INFO] [stderr]  --> src/communicator/lib/mod.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     pub fn middle_function() {
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `middle_secret_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:10:5
[INFO] [stderr]    |
[INFO] [stderr] 10 |     fn middle_secret_function() {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `inner_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:17:9
[INFO] [stderr]    |
[INFO] [stderr] 17 |         pub fn inner_function() {}
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `secret_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |         fn secret_function() {
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `inner_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:26:13
[INFO] [stderr]    |
[INFO] [stderr] 26 |             pub fn inner_function() {
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `try_me`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:56:1
[INFO] [stderr]    |
[INFO] [stderr] 56 | fn try_me() {
[INFO] [stderr]    | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `prints_and_returns_10`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:89:1
[INFO] [stderr]    |
[INFO] [stderr] 89 | fn prints_and_returns_10(a: i32) -> i32 {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `middle_function`
[INFO] [stderr]  --> src/communicator/lib/mod.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     pub fn middle_function() {
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `middle_secret_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:10:5
[INFO] [stderr]    |
[INFO] [stderr] 10 |     fn middle_secret_function() {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `inner_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:17:9
[INFO] [stderr]    |
[INFO] [stderr] 17 |         pub fn inner_function() {}
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `secret_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |         fn secret_function() {
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `inner_function`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:26:13
[INFO] [stderr]    |
[INFO] [stderr] 26 |             pub fn inner_function() {
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `try_me`
[INFO] [stderr]   --> src/communicator/lib/mod.rs:56:1
[INFO] [stderr]    |
[INFO] [stderr] 56 | fn try_me() {
[INFO] [stderr]    | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary parentheses around assigned value
[INFO] [stderr]    --> src/collections/bin/main.rs:181:14
[INFO] [stderr]     |
[INFO] [stderr] 181 |         t += (*i as f32);
[INFO] [stderr]     |              ^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_parens)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary parentheses around assigned value
[INFO] [stderr]    --> src/collections/bin/main.rs:181:14
[INFO] [stderr]     |
[INFO] [stderr] 181 |         t += (*i as f32);
[INFO] [stderr]     |              ^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_parens)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `ip_type`
[INFO] [stderr]  --> src/chapter6/bin/main.rs:1:10
[INFO] [stderr]   |
[INFO] [stderr] 1 | fn route(ip_type: IpAddrKind) { }
[INFO] [stderr]   |          ^^^^^^^ help: consider prefixing with an underscore: `_ip_type`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:32:35
[INFO] [stderr]    |
[INFO] [stderr] 32 |     let x = some_string.and_then(|x: &str| Some("sf"));
[INFO] [stderr]    |                                   ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `six`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:11:9
[INFO] [stderr]    |
[INFO] [stderr] 11 |     let six = IpAddrKind::V6;
[INFO] [stderr]    |         ^^^ help: consider prefixing with an underscore: `_six`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `home`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:18:9
[INFO] [stderr]    |
[INFO] [stderr] 18 |     let home = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_home`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `loopback`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |     let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stderr]    |         ^^^^^^^^ help: consider prefixing with an underscore: `_loopback`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `home`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:21:9
[INFO] [stderr]    |
[INFO] [stderr] 21 |     let home = IpAddr2::V4(127, 0, 0, 1);
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_home`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `loopback`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:22:9
[INFO] [stderr]    |
[INFO] [stderr] 22 |     let loopback = IpAddr2::V6(String::from("::1"));
[INFO] [stderr]    |         ^^^^^^^^ help: consider prefixing with an underscore: `_loopback`
[INFO] [stderr] 
[INFO] [stderr] warning: variable `count` is assigned to, but never used
[INFO] [stderr]   --> src/chapter6/bin/main.rs:72:13
[INFO] [stderr]    |
[INFO] [stderr] 72 |     let mut count = 0;
[INFO] [stderr]    |             ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: consider using `_count` instead
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `count` is never read
[INFO] [stderr]   --> src/chapter6/bin/main.rs:76:9
[INFO] [stderr]    |
[INFO] [stderr] 76 |         count += 1;
[INFO] [stderr]    |         ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_assignments)] on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Quit`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:94:5
[INFO] [stderr]    |
[INFO] [stderr] 94 |     Quit,
[INFO] [stderr]    |     ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Move`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:95:5
[INFO] [stderr]    |
[INFO] [stderr] 95 |     Move { x: i32, y: i32 },
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `ChangeColor`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:97:5
[INFO] [stderr]    |
[INFO] [stderr] 97 |     ChangeColor(i32, i32, i32),
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Alaska`
[INFO] [stderr]    --> src/chapter6/bin/main.rs:115:5
[INFO] [stderr]     |
[INFO] [stderr] 115 |     Alaska,
[INFO] [stderr]     |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Nickel`
[INFO] [stderr]    --> src/chapter6/bin/main.rs:121:5
[INFO] [stderr]     |
[INFO] [stderr] 121 |     Nickel,
[INFO] [stderr]     |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `Red`, `Yellow`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:3:34
[INFO] [stderr]   |
[INFO] [stderr] 3 | use communicator::TrafficLight::{Red, Yellow};
[INFO] [stderr]   |                                  ^^^  ^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `max_ch`
[INFO] [stderr]   --> src/generics/bin/main.rs:51:1
[INFO] [stderr]    |
[INFO] [stderr] 51 | fn max_ch(list: &[char]) -> Option<char> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `red`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:8:9
[INFO] [stderr]   |
[INFO] [stderr] 8 |     let red = Red;
[INFO] [stderr]   |         ^^^ help: consider prefixing with an underscore: `_red`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `yellow`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:9:9
[INFO] [stderr]   |
[INFO] [stderr] 9 |     let yellow = Yellow;
[INFO] [stderr]   |         ^^^^^^ help: consider prefixing with an underscore: `_yellow`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `green`
[INFO] [stderr]   --> src/chapter7/bin/main.rs:10:9
[INFO] [stderr]    |
[INFO] [stderr] 10 |     let green = communicator::TrafficLight::Green;
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_green`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `green`
[INFO] [stderr]   --> src/chapter7/bin/main.rs:14:9
[INFO] [stderr]    |
[INFO] [stderr] 14 |     let green = Green;
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_green`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s1`
[INFO] [stderr]   --> src/collections/bin/main.rs:99:9
[INFO] [stderr]    |
[INFO] [stderr] 99 |     let s1 = String::from("hello");
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `scores`
[INFO] [stderr]    --> src/collections/bin/main.rs:143:9
[INFO] [stderr]     |
[INFO] [stderr] 143 |     let scores: HashMap<_, _> = zipped.collect();
[INFO] [stderr]     |         ^^^^^^ help: consider prefixing with an underscore: `_scores`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/collections/bin/main.rs:56:9
[INFO] [stderr]    |
[INFO] [stderr] 56 |     let mut s = String::new();
[INFO] [stderr]    |         ----^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `black`
[INFO] [stderr]   --> src/chapter5/bin/main.rs:23:9
[INFO] [stderr]    |
[INFO] [stderr] 23 |     let black = Color(0, 0, 0);
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_black`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `origin`
[INFO] [stderr]   --> src/chapter5/bin/main.rs:24:9
[INFO] [stderr]    |
[INFO] [stderr] 24 |     let origin = Point(0, 0, 0);
[INFO] [stderr]    |         ^^^^^^ help: consider prefixing with an underscore: `_origin`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/chapter5/bin/main.rs:103:1
[INFO] [stderr]     |
[INFO] [stderr] 103 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s1`
[INFO] [stderr]   --> src/collections/bin/main.rs:99:9
[INFO] [stderr]    |
[INFO] [stderr] 99 |     let s1 = String::from("hello");
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `scores`
[INFO] [stderr]    --> src/collections/bin/main.rs:143:9
[INFO] [stderr]     |
[INFO] [stderr] 143 |     let scores: HashMap<_, _> = zipped.collect();
[INFO] [stderr]     |         ^^^^^^ help: consider prefixing with an underscore: `_scores`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `t`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:24
[INFO] [stderr]    |
[INFO] [stderr] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr]    |                        ^ help: consider prefixing with an underscore: `_t`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `u`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:30
[INFO] [stderr]    |
[INFO] [stderr] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr]    |                              ^ help: consider prefixing with an underscore: `_u`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `some_function`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:1
[INFO] [stderr]    |
[INFO] [stderr] 83 | / fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr] 84 | |     where T: std::fmt::Display + Clone,
[INFO] [stderr] 85 | |           U: Clone + std::fmt::Debug {
[INFO] [stderr] 86 | |     1
[INFO] [stderr] 87 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Pair`
[INFO] [stderr]   --> src/traits/bin/main.rs:92:1
[INFO] [stderr]    |
[INFO] [stderr] 92 | struct Pair<T> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/traits/bin/main.rs:98:5
[INFO] [stderr]    |
[INFO] [stderr] 98 |     fn new(x: T, y: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `cmp_display`
[INFO] [stderr]    --> src/traits/bin/main.rs:107:5
[INFO] [stderr]     |
[INFO] [stderr] 107 |     fn cmp_display(&self) {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `black`
[INFO] [stderr]   --> src/chapter5/bin/main.rs:23:9
[INFO] [stderr]    |
[INFO] [stderr] 23 |     let black = Color(0, 0, 0);
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_black`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `origin`
[INFO] [stderr]   --> src/chapter5/bin/main.rs:24:9
[INFO] [stderr]    |
[INFO] [stderr] 24 |     let origin = Point(0, 0, 0);
[INFO] [stderr]    |         ^^^^^^ help: consider prefixing with an underscore: `_origin`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/collections/bin/main.rs:56:9
[INFO] [stderr]    |
[INFO] [stderr] 56 |     let mut s = String::new();
[INFO] [stderr]    |         ----^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/chapter5/bin/main.rs:103:1
[INFO] [stderr]     |
[INFO] [stderr] 103 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `Red`, `Yellow`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:3:34
[INFO] [stderr]   |
[INFO] [stderr] 3 | use communicator::TrafficLight::{Red, Yellow};
[INFO] [stderr]   |                                  ^^^  ^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `red`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:8:9
[INFO] [stderr]   |
[INFO] [stderr] 8 |     let red = Red;
[INFO] [stderr]   |         ^^^ help: consider prefixing with an underscore: `_red`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `yellow`
[INFO] [stderr]  --> src/chapter7/bin/main.rs:9:9
[INFO] [stderr]   |
[INFO] [stderr] 9 |     let yellow = Yellow;
[INFO] [stderr]   |         ^^^^^^ help: consider prefixing with an underscore: `_yellow`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `green`
[INFO] [stderr]   --> src/chapter7/bin/main.rs:10:9
[INFO] [stderr]    |
[INFO] [stderr] 10 |     let green = communicator::TrafficLight::Green;
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_green`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `green`
[INFO] [stderr]   --> src/chapter7/bin/main.rs:14:9
[INFO] [stderr]    |
[INFO] [stderr] 14 |     let green = Green;
[INFO] [stderr]    |         ^^^^^ help: consider prefixing with an underscore: `_green`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `v`
[INFO] [stderr]  --> src/errors/bin/main.rs:5:9
[INFO] [stderr]   |
[INFO] [stderr] 5 |     let v = vec![1, 2, 3];
[INFO] [stderr]   |         ^ help: consider prefixing with an underscore: `_v`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `f`
[INFO] [stderr]   --> src/errors/bin/main.rs:23:9
[INFO] [stderr]    |
[INFO] [stderr] 23 |     let f = match f {
[INFO] [stderr]    |         ^ help: consider prefixing with an underscore: `_f`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `t`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:24
[INFO] [stderr]    |
[INFO] [stderr] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr]    |                        ^ help: consider prefixing with an underscore: `_t`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `u`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:30
[INFO] [stderr]    |
[INFO] [stderr] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr]    |                              ^ help: consider prefixing with an underscore: `_u`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `some_function`
[INFO] [stderr]   --> src/traits/bin/main.rs:83:1
[INFO] [stderr]    |
[INFO] [stderr] 83 | / fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stderr] 84 | |     where T: std::fmt::Display + Clone,
[INFO] [stderr] 85 | |           U: Clone + std::fmt::Debug {
[INFO] [stderr] 86 | |     1
[INFO] [stderr] 87 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Pair`
[INFO] [stderr]   --> src/traits/bin/main.rs:92:1
[INFO] [stderr]    |
[INFO] [stderr] 92 | struct Pair<T> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/traits/bin/main.rs:98:5
[INFO] [stderr]    |
[INFO] [stderr] 98 |     fn new(x: T, y: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `cmp_display`
[INFO] [stderr]    --> src/traits/bin/main.rs:107:5
[INFO] [stderr]     |
[INFO] [stderr] 107 |     fn cmp_display(&self) {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `read_username_from_file`
[INFO] [stderr]   --> src/errors/bin/main.rs:44:1
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `read_username_from_file2`
[INFO] [stderr]   --> src/errors/bin/main.rs:60:1
[INFO] [stderr]    |
[INFO] [stderr] 60 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function `openFile` should have a snake case name
[INFO] [stderr]   --> src/errors/bin/main.rs:20:4
[INFO] [stderr]    |
[INFO] [stderr] 20 | fn openFile() {
[INFO] [stderr]    |    ^^^^^^^^ help: convert the identifier to snake case: `open_file`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_snake_case)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s`
[INFO] [stderr]  --> src/lifetimes/bin/main.rs:5:13
[INFO] [stderr]   |
[INFO] [stderr] 5 |         let s: &'static str = "asdsa";
[INFO] [stderr]   |             ^ help: consider prefixing with an underscore: `_s`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:40:29
[INFO] [stderr]    |
[INFO] [stderr] 40 | fn longest2<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    |                             ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:44:29
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    |                             ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `longest3`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:44:1
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never used: `a`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:50:5
[INFO] [stderr]    |
[INFO] [stderr] 50 |     a: String,
[INFO] [stderr]    |     ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `level`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:54:5
[INFO] [stderr]    |
[INFO] [stderr] 54 |     fn level(&self) -> i32 {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `a`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:60:5
[INFO] [stderr]    |
[INFO] [stderr] 60 |     fn a(&self) -> &str {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `longest_with_an_announcement`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:67:1
[INFO] [stderr]    |
[INFO] [stderr] 67 | / fn longest_with_an_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
[INFO] [stderr] 68 | |     where T: Display
[INFO] [stderr] 69 | | {
[INFO] [stderr] 70 | |     println!("Announcement! {}", ann);
[INFO] [stderr] ...  |
[INFO] [stderr] 75 | |     }
[INFO] [stderr] 76 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s`
[INFO] [stderr]  --> src/lifetimes/bin/main.rs:5:13
[INFO] [stderr]   |
[INFO] [stderr] 5 |         let s: &'static str = "asdsa";
[INFO] [stderr]   |             ^ help: consider prefixing with an underscore: `_s`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:40:29
[INFO] [stderr]    |
[INFO] [stderr] 40 | fn longest2<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    |                             ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:44:29
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    |                             ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `black`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:107:9
[INFO] [stderr]     |
[INFO] [stderr] 107 |     let black = Color(0, 0, 0);
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_black`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `origin`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:108:9
[INFO] [stderr]     |
[INFO] [stderr] 108 |     let origin = Point(0, 0, 0);
[INFO] [stderr]     |         ^^^^^^ help: consider prefixing with an underscore: `_origin`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `longest3`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:44:1
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never used: `a`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:50:5
[INFO] [stderr]    |
[INFO] [stderr] 50 |     a: String,
[INFO] [stderr]    |     ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `level`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:54:5
[INFO] [stderr]    |
[INFO] [stderr] 54 |     fn level(&self) -> i32 {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `a`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:60:5
[INFO] [stderr]    |
[INFO] [stderr] 60 |     fn a(&self) -> &str {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `longest_with_an_announcement`
[INFO] [stderr]   --> src/lifetimes/bin/main.rs:67:1
[INFO] [stderr]    |
[INFO] [stderr] 67 | / fn longest_with_an_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
[INFO] [stderr] 68 | |     where T: Display
[INFO] [stderr] 69 | | {
[INFO] [stderr] 70 | |     println!("Announcement! {}", ann);
[INFO] [stderr] ...  |
[INFO] [stderr] 75 | |     }
[INFO] [stderr] 76 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `ip_type`
[INFO] [stderr]  --> src/chapter6/bin/main.rs:1:10
[INFO] [stderr]   |
[INFO] [stderr] 1 | fn route(ip_type: IpAddrKind) { }
[INFO] [stderr]   |          ^^^^^^^ help: consider prefixing with an underscore: `_ip_type`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:32:35
[INFO] [stderr]    |
[INFO] [stderr] 32 |     let x = some_string.and_then(|x: &str| Some("sf"));
[INFO] [stderr]    |                                   ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `six`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:11:9
[INFO] [stderr]    |
[INFO] [stderr] 11 |     let six = IpAddrKind::V6;
[INFO] [stderr]    |         ^^^ help: consider prefixing with an underscore: `_six`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `home`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:18:9
[INFO] [stderr]    |
[INFO] [stderr] 18 |     let home = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_home`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `loopback`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:19:9
[INFO] [stderr]    |
[INFO] [stderr] 19 |     let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stderr]    |         ^^^^^^^^ help: consider prefixing with an underscore: `_loopback`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `home`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:21:9
[INFO] [stderr]    |
[INFO] [stderr] 21 |     let home = IpAddr2::V4(127, 0, 0, 1);
[INFO] [stderr]    |         ^^^^ help: consider prefixing with an underscore: `_home`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `loopback`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:22:9
[INFO] [stderr]    |
[INFO] [stderr] 22 |     let loopback = IpAddr2::V6(String::from("::1"));
[INFO] [stderr]    |         ^^^^^^^^ help: consider prefixing with an underscore: `_loopback`
[INFO] [stderr] 
[INFO] [stderr] warning: variable `count` is assigned to, but never used
[INFO] [stderr]   --> src/chapter6/bin/main.rs:72:13
[INFO] [stderr]    |
[INFO] [stderr] 72 |     let mut count = 0;
[INFO] [stderr]    |             ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: consider using `_count` instead
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `count` is never read
[INFO] [stderr]   --> src/chapter6/bin/main.rs:76:9
[INFO] [stderr]    |
[INFO] [stderr] 76 |         count += 1;
[INFO] [stderr]    |         ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_assignments)] on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `black`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:107:9
[INFO] [stderr]     |
[INFO] [stderr] 107 |     let black = Color(0, 0, 0);
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_black`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `origin`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:108:9
[INFO] [stderr]     |
[INFO] [stderr] 108 |     let origin = Point(0, 0, 0);
[INFO] [stderr]     |         ^^^^^^ help: consider prefixing with an underscore: `_origin`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Quit`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:94:5
[INFO] [stderr]    |
[INFO] [stderr] 94 |     Quit,
[INFO] [stderr]    |     ^^^^
[INFO] [stderr]    |
[INFO] [stderr] warning: function is never used: `gives_ownership`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:119:1
[INFO] [stderr]     |
[INFO] [stderr] 119 | fn gives_ownership() -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_and_gives_back`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:124:1
[INFO] [stderr]     |
[INFO] [stderr] 124 | fn takes_and_gives_back(a_string: String) -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `no_dangle`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:149:1
[INFO] [stderr]     |
[INFO] [stderr] 149 | fn no_dangle() -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:187:1
[INFO] [stderr]     |
[INFO] [stderr] 187 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Move`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:95:5
[INFO] [stderr]    |
[INFO] [stderr] 95 |     Move { x: i32, y: i32 },
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `ChangeColor`
[INFO] [stderr]   --> src/chapter6/bin/main.rs:97:5
[INFO] [stderr]    |
[INFO] [stderr] 97 |     ChangeColor(i32, i32, i32),
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Alaska`
[INFO] [stderr]    --> src/chapter6/bin/main.rs:115:5
[INFO] [stderr]     |
[INFO] [stderr] 115 |     Alaska,
[INFO] [stderr]     |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Nickel`
[INFO] [stderr]    --> src/chapter6/bin/main.rs:121:5
[INFO] [stderr]     |
[INFO] [stderr] 121 |     Nickel,
[INFO] [stderr]     |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `gives_ownership`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:119:1
[INFO] [stderr]     |
[INFO] [stderr] 119 | fn gives_ownership() -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_and_gives_back`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:124:1
[INFO] [stderr]     |
[INFO] [stderr] 124 | fn takes_and_gives_back(a_string: String) -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `no_dangle`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:149:1
[INFO] [stderr]     |
[INFO] [stderr] 149 | fn no_dangle() -> String {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/chapter3/bin/main.rs:187:1
[INFO] [stderr]     |
[INFO] [stderr] 187 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `max_ch`
[INFO] [stderr]   --> src/generics/bin/main.rs:51:1
[INFO] [stderr]    |
[INFO] [stderr] 51 | fn max_ch(list: &[char]) -> Option<char> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `v`
[INFO] [stderr]  --> src/errors/bin/main.rs:5:9
[INFO] [stderr]   |
[INFO] [stderr] 5 |     let v = vec![1, 2, 3];
[INFO] [stderr]   |         ^ help: consider prefixing with an underscore: `_v`
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `f`
[INFO] [stderr]   --> src/errors/bin/main.rs:23:9
[INFO] [stderr]    |
[INFO] [stderr] 23 |     let f = match f {
[INFO] [stderr]    |         ^ help: consider prefixing with an underscore: `_f`
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `read_username_from_file`
[INFO] [stderr]   --> src/errors/bin/main.rs:44:1
[INFO] [stderr]    |
[INFO] [stderr] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `read_username_from_file2`
[INFO] [stderr]   --> src/errors/bin/main.rs:60:1
[INFO] [stderr]    |
[INFO] [stderr] 60 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function `openFile` should have a snake case name
[INFO] [stderr]   --> src/errors/bin/main.rs:20:4
[INFO] [stderr]    |
[INFO] [stderr] 20 | fn openFile() {
[INFO] [stderr]    |    ^^^^^^^^ help: convert the identifier to snake case: `open_file`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_snake_case)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.77s
[INFO] running `"docker" "inspect" "f8cabf72f35cfa047e2623c3a81447510660fb2a7666751d6488bffaa59bef31"`
[INFO] running `"docker" "rm" "-f" "f8cabf72f35cfa047e2623c3a81447510660fb2a7666751d6488bffaa59bef31"`
[INFO] [stdout] f8cabf72f35cfa047e2623c3a81447510660fb2a7666751d6488bffaa59bef31