[INFO] cloning repository https://github.com/ICimpoes/rusty-train
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ICimpoes/rusty-train" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FICimpoes%2Frusty-train", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FICimpoes%2Frusty-train'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f5849823762ca3e361642003d886bc612bb14d8c
[INFO] checking ICimpoes/rusty-train against master#a609fb45efad59dfd459c76e50899be9f0583b5a for pr-80579
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FICimpoes%2Frusty-train" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ICimpoes/rusty-train on toolchain a609fb45efad59dfd459c76e50899be9f0583b5a
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ICimpoes/rusty-train
[INFO] finished tweaking git repo https://github.com/ICimpoes/rusty-train
[INFO] tweaked toml for git repo https://github.com/ICimpoes/rusty-train written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/ICimpoes/rusty-train already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f794a567cbd0078270a0bf425338359383116127dd7e80cafb565a985a008cfe
[INFO] running `Command { std: "docker" "start" "-a" "f794a567cbd0078270a0bf425338359383116127dd7e80cafb565a985a008cfe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f794a567cbd0078270a0bf425338359383116127dd7e80cafb565a985a008cfe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f794a567cbd0078270a0bf425338359383116127dd7e80cafb565a985a008cfe", kill_on_drop: false }`
[INFO] [stdout] f794a567cbd0078270a0bf425338359383116127dd7e80cafb565a985a008cfe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 20cf46ea21f93179d335a217b6e0c67bda341b480d5f52a49f61213dfa703dc4
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "20cf46ea21f93179d335a217b6e0c67bda341b480d5f52a49f61213dfa703dc4", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking libc v0.2.40
[INFO] [stderr]     Checking rand v0.4.2
[INFO] [stderr]     Checking rusty-train v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function is never used: `middle_function`
[INFO] [stdout]  --> src/communicator/lib/mod.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 |     pub fn middle_function() {
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `middle_secret_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:10:8
[INFO] [stdout]    |
[INFO] [stdout] 10 |     fn middle_secret_function() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `inner_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:17:16
[INFO] [stdout]    |
[INFO] [stdout] 17 |         pub fn inner_function() {}
[INFO] [stdout]    |                ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `secret_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:19:12
[INFO] [stdout]    |
[INFO] [stdout] 19 |         fn secret_function() {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `inner_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:26:20
[INFO] [stdout]    |
[INFO] [stdout] 26 |             pub fn inner_function() {
[INFO] [stdout]    |                    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `try_me`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:56:4
[INFO] [stdout]    |
[INFO] [stdout] 56 | fn try_me() {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `prints_and_returns_10`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:89:4
[INFO] [stdout]    |
[INFO] [stdout] 89 | fn prints_and_returns_10(a: i32) -> i32 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `middle_function`
[INFO] [stdout]  --> src/communicator/lib/mod.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 |     pub fn middle_function() {
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `middle_secret_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:10:8
[INFO] [stdout]    |
[INFO] [stdout] 10 |     fn middle_secret_function() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `inner_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:17:16
[INFO] [stdout]    |
[INFO] [stdout] 17 |         pub fn inner_function() {}
[INFO] [stdout]    |                ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `secret_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:19:12
[INFO] [stdout]    |
[INFO] [stdout] 19 |         fn secret_function() {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `inner_function`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:26:20
[INFO] [stdout]    |
[INFO] [stdout] 26 |             pub fn inner_function() {
[INFO] [stdout]    |                    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `try_me`
[INFO] [stdout]   --> src/communicator/lib/mod.rs:56:4
[INFO] [stdout]    |
[INFO] [stdout] 56 | fn try_me() {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Red`, `Yellow`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:3:34
[INFO] [stdout]   |
[INFO] [stdout] 3 | use communicator::TrafficLight::{Red, Yellow};
[INFO] [stdout]   |                                  ^^^  ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]  --> src/lifetimes/bin/main.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let s: &'static str = "asdsa";
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:40:29
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn longest2<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |                             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:44:29
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |                             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `longest3`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `a`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:50:5
[INFO] [stdout]    |
[INFO] [stdout] 50 |     a: String,
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `level`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:54:8
[INFO] [stdout]    |
[INFO] [stdout] 54 |     fn level(&self) -> i32 {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `a`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:60:8
[INFO] [stdout]    |
[INFO] [stdout] 60 |     fn a(&self) -> &str {
[INFO] [stdout]    |        ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `longest_with_an_announcement`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:67:4
[INFO] [stdout]    |
[INFO] [stdout] 67 | fn longest_with_an_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `red`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let red = Red;
[INFO] [stdout]   |         ^^^ help: if this is intentional, prefix it with an underscore: `_red`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `yellow`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let yellow = Yellow;
[INFO] [stdout]   |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_yellow`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `green`
[INFO] [stdout]   --> src/chapter7/bin/main.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     let green = communicator::TrafficLight::Green;
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_green`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `green`
[INFO] [stdout]   --> src/chapter7/bin/main.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let green = Green;
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_green`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `HashMap` is imported redundantly
[INFO] [stdout]    --> src/collections/bin/main.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 1   | use std::collections::HashMap;
[INFO] [stdout]     |     ------------------------- the item `HashMap` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 122 |     use std::collections::HashMap;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]    --> src/collections/bin/main.rs:181:14
[INFO] [stdout]     |
[INFO] [stdout] 181 |         t += (*i as f32);
[INFO] [stdout]     |              ^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:24
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |                        ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:30
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |                              ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `some_function`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:4
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Pair`
[INFO] [stdout]   --> src/traits/bin/main.rs:92:8
[INFO] [stdout]    |
[INFO] [stdout] 92 | struct Pair<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/traits/bin/main.rs:98:8
[INFO] [stdout]    |
[INFO] [stdout] 98 |     fn new(x: T, y: T) -> Self {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `cmp_display`
[INFO] [stdout]    --> src/traits/bin/main.rs:107:8
[INFO] [stdout]     |
[INFO] [stdout] 107 |     fn cmp_display(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]  --> src/lifetimes/bin/main.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let s: &'static str = "asdsa";
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:40:29
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn longest2<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |                             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:44:29
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |                             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:107:9
[INFO] [stdout]     |
[INFO] [stdout] 107 |     let black = Color(0, 0, 0);
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:108:9
[INFO] [stdout]     |
[INFO] [stdout] 108 |     let origin = Point(0, 0, 0);
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_origin`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `gives_ownership`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:119:4
[INFO] [stdout]     |
[INFO] [stdout] 119 | fn gives_ownership() -> String {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `takes_and_gives_back`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:124:4
[INFO] [stdout]     |
[INFO] [stdout] 124 | fn takes_and_gives_back(a_string: String) -> String {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/errors/bin/main.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let v = vec![1, 2, 3];
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/errors/bin/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let f = match f {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `no_dangle`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:149:4
[INFO] [stdout]     |
[INFO] [stdout] 149 | fn no_dangle() -> String {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `build_user`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:187:4
[INFO] [stdout]     |
[INFO] [stdout] 187 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]   --> src/chapter5/bin/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let black = Color(0, 0, 0);
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]   --> src/chapter5/bin/main.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let origin = Point(0, 0, 0);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_origin`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `longest3`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn longest3<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `a`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:50:5
[INFO] [stdout]    |
[INFO] [stdout] 50 |     a: String,
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `level`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:54:8
[INFO] [stdout]    |
[INFO] [stdout] 54 |     fn level(&self) -> i32 {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `a`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:60:8
[INFO] [stdout]    |
[INFO] [stdout] 60 |     fn a(&self) -> &str {
[INFO] [stdout]    |        ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `longest_with_an_announcement`
[INFO] [stdout]   --> src/lifetimes/bin/main.rs:67:4
[INFO] [stdout]    |
[INFO] [stdout] 67 | fn longest_with_an_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/errors/bin/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file2`
[INFO] [stdout]   --> src/errors/bin/main.rs:60:4
[INFO] [stdout]    |
[INFO] [stdout] 60 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `openFile` should have a snake case name
[INFO] [stdout]   --> src/errors/bin/main.rs:20:4
[INFO] [stdout]    |
[INFO] [stdout] 20 | fn openFile() {
[INFO] [stdout]    |    ^^^^^^^^ help: convert the identifier to snake case: `open_file`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `build_user`
[INFO] [stdout]    --> src/chapter5/bin/main.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `max_ch`
[INFO] [stdout]   --> src/generics/bin/main.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn max_ch(list: &[char]) -> Option<char> {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]   --> src/collections/bin/main.rs:99:9
[INFO] [stdout]    |
[INFO] [stdout] 99 |     let s1 = String::from("hello");
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `scores`
[INFO] [stdout]    --> src/collections/bin/main.rs:143:9
[INFO] [stdout]     |
[INFO] [stdout] 143 |     let scores: HashMap<_, _> = zipped.collect();
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_scores`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `HashMap` is imported redundantly
[INFO] [stdout]    --> src/collections/bin/main.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 1   | use std::collections::HashMap;
[INFO] [stdout]     |     ------------------------- the item `HashMap` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 122 |     use std::collections::HashMap;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]    --> src/collections/bin/main.rs:181:14
[INFO] [stdout]     |
[INFO] [stdout] 181 |         t += (*i as f32);
[INFO] [stdout]     |              ^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:24
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |                        ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:30
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |                              ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `some_function`
[INFO] [stdout]   --> src/traits/bin/main.rs:83:4
[INFO] [stdout]    |
[INFO] [stdout] 83 | fn some_function<T, U>(t: T, u: U) -> i32
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Pair`
[INFO] [stdout]   --> src/traits/bin/main.rs:92:8
[INFO] [stdout]    |
[INFO] [stdout] 92 | struct Pair<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/traits/bin/main.rs:98:8
[INFO] [stdout]    |
[INFO] [stdout] 98 |     fn new(x: T, y: T) -> Self {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `cmp_display`
[INFO] [stdout]    --> src/traits/bin/main.rs:107:8
[INFO] [stdout]     |
[INFO] [stdout] 107 |     fn cmp_display(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/errors/bin/main.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let v = vec![1, 2, 3];
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/errors/bin/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let f = match f {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `max_ch`
[INFO] [stdout]   --> src/generics/bin/main.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn max_ch(list: &[char]) -> Option<char> {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_type`
[INFO] [stdout]  --> src/chapter6/bin/main.rs:1:10
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn route(ip_type: IpAddrKind) { }
[INFO] [stdout]   |          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_type`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:32:35
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let x = some_string.and_then(|x: &str| Some("sf"));
[INFO] [stdout]    |                                   ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:11:9
[INFO] [stdout]    |
[INFO] [stdout] 11 |     let six = IpAddrKind::V6;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let home = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let home = IpAddr2::V4(127, 0, 0, 1);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let loopback = IpAddr2::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]   --> src/chapter6/bin/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let mut count = 0;
[INFO] [stdout]    |         ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_count` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]   --> src/chapter6/bin/main.rs:76:9
[INFO] [stdout]    |
[INFO] [stdout] 76 |         count += 1;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/errors/bin/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file2`
[INFO] [stdout]   --> src/errors/bin/main.rs:60:4
[INFO] [stdout]    |
[INFO] [stdout] 60 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `openFile` should have a snake case name
[INFO] [stdout]   --> src/errors/bin/main.rs:20:4
[INFO] [stdout]    |
[INFO] [stdout] 20 | fn openFile() {
[INFO] [stdout]    |    ^^^^^^^^ help: convert the identifier to snake case: `open_file`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Quit`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:94:5
[INFO] [stdout]    |
[INFO] [stdout] 94 |     Quit,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Move`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:95:5
[INFO] [stdout]    |
[INFO] [stdout] 95 |     Move { x: i32, y: i32 },
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `ChangeColor`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:97:5
[INFO] [stdout]    |
[INFO] [stdout] 97 |     ChangeColor(i32, i32, i32),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alaska`
[INFO] [stdout]    --> src/chapter6/bin/main.rs:115:5
[INFO] [stdout]     |
[INFO] [stdout] 115 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]    --> src/chapter6/bin/main.rs:121:5
[INFO] [stdout]     |
[INFO] [stdout] 121 |     Nickel,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/collections/bin/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let mut s = String::new();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 14 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Red`, `Yellow`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:3:34
[INFO] [stdout]   |
[INFO] [stdout] 3 | use communicator::TrafficLight::{Red, Yellow};
[INFO] [stdout]   |                                  ^^^  ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:107:9
[INFO] [stdout]     |
[INFO] [stdout] 107 |     let black = Color(0, 0, 0);
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:108:9
[INFO] [stdout]     |
[INFO] [stdout] 108 |     let origin = Point(0, 0, 0);
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_origin`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `red`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let red = Red;
[INFO] [stdout]   |         ^^^ help: if this is intentional, prefix it with an underscore: `_red`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `yellow`
[INFO] [stdout]  --> src/chapter7/bin/main.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let yellow = Yellow;
[INFO] [stdout]   |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_yellow`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `green`
[INFO] [stdout]   --> src/chapter7/bin/main.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     let green = communicator::TrafficLight::Green;
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_green`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `green`
[INFO] [stdout]   --> src/chapter7/bin/main.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let green = Green;
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_green`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `gives_ownership`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:119:4
[INFO] [stdout]     |
[INFO] [stdout] 119 | fn gives_ownership() -> String {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `takes_and_gives_back`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:124:4
[INFO] [stdout]     |
[INFO] [stdout] 124 | fn takes_and_gives_back(a_string: String) -> String {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `no_dangle`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:149:4
[INFO] [stdout]     |
[INFO] [stdout] 149 | fn no_dangle() -> String {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `build_user`
[INFO] [stdout]    --> src/chapter3/bin/main.rs:187:4
[INFO] [stdout]     |
[INFO] [stdout] 187 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]   --> src/collections/bin/main.rs:99:9
[INFO] [stdout]    |
[INFO] [stdout] 99 |     let s1 = String::from("hello");
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `scores`
[INFO] [stdout]    --> src/collections/bin/main.rs:143:9
[INFO] [stdout]     |
[INFO] [stdout] 143 |     let scores: HashMap<_, _> = zipped.collect();
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_scores`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_type`
[INFO] [stdout]  --> src/chapter6/bin/main.rs:1:10
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn route(ip_type: IpAddrKind) { }
[INFO] [stdout]   |          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_type`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:32:35
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let x = some_string.and_then(|x: &str| Some("sf"));
[INFO] [stdout]    |                                   ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:11:9
[INFO] [stdout]    |
[INFO] [stdout] 11 |     let six = IpAddrKind::V6;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let home = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let home = IpAddr2::V4(127, 0, 0, 1);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let loopback = IpAddr2::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]   --> src/chapter6/bin/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let mut count = 0;
[INFO] [stdout]    |         ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_count` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]   --> src/chapter6/bin/main.rs:76:9
[INFO] [stdout]    |
[INFO] [stdout] 76 |         count += 1;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Quit`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:94:5
[INFO] [stdout]    |
[INFO] [stdout] 94 |     Quit,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Move`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:95:5
[INFO] [stdout]    |
[INFO] [stdout] 95 |     Move { x: i32, y: i32 },
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `ChangeColor`
[INFO] [stdout]   --> src/chapter6/bin/main.rs:97:5
[INFO] [stdout]    |
[INFO] [stdout] 97 |     ChangeColor(i32, i32, i32),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alaska`
[INFO] [stdout]    --> src/chapter6/bin/main.rs:115:5
[INFO] [stdout]     |
[INFO] [stdout] 115 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]    --> src/chapter6/bin/main.rs:121:5
[INFO] [stdout]     |
[INFO] [stdout] 121 |     Nickel,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/collections/bin/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let mut s = String::new();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 14 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]   --> src/chapter5/bin/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let black = Color(0, 0, 0);
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]   --> src/chapter5/bin/main.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let origin = Point(0, 0, 0);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_origin`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `build_user`
[INFO] [stdout]    --> src/chapter5/bin/main.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.04s
[INFO] running `Command { std: "docker" "inspect" "20cf46ea21f93179d335a217b6e0c67bda341b480d5f52a49f61213dfa703dc4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "20cf46ea21f93179d335a217b6e0c67bda341b480d5f52a49f61213dfa703dc4", kill_on_drop: false }`
[INFO] [stdout] 20cf46ea21f93179d335a217b6e0c67bda341b480d5f52a49f61213dfa703dc4