[INFO] cloning repository https://github.com/sss-mykw/Rust-Programming-launguage
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sss-mykw/Rust-Programming-launguage" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage'...
[INFO] [stderr] error: copy-fd: write returned: No space left on device
[INFO] [stderr] fatal: cannot copy '/usr/share/git-core/templates/hooks/pre-applypatch.sample' to '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage/hooks/pre-applypatch.sample': No space left on device
[WARN] Retrying crate fetch in 3 seconds (attempt 1)
[INFO] cloning repository https://github.com/sss-mykw/Rust-Programming-launguage
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sss-mykw/Rust-Programming-launguage" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ee3f8a703bbbc8e5c94a38dc71cf7c42fc90cb88
[INFO] checking sss-mykw/Rust-Programming-launguage against master#32cd9114712a24010b0583624dc52ac302194128 for pr-143717
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsss-mykw%2FRust-Programming-launguage" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/sss-mykw/Rust-Programming-launguage
[INFO] finished tweaking git repo https://github.com/sss-mykw/Rust-Programming-launguage
[INFO] tweaked toml for git repo https://github.com/sss-mykw/Rust-Programming-launguage written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/sss-mykw/Rust-Programming-launguage on toolchain 32cd9114712a24010b0583624dc52ac302194128
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+32cd9114712a24010b0583624dc52ac302194128" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/sss-mykw/Rust-Programming-launguage already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+32cd9114712a24010b0583624dc52ac302194128" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+32cd9114712a24010b0583624dc52ac302194128" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5d057a0c809993f2b173dfe5cf31f2e4853bd0cede07ab8853024c2e5050bb35
[INFO] running `Command { std: "docker" "start" "-a" "5d057a0c809993f2b173dfe5cf31f2e4853bd0cede07ab8853024c2e5050bb35", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5d057a0c809993f2b173dfe5cf31f2e4853bd0cede07ab8853024c2e5050bb35", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5d057a0c809993f2b173dfe5cf31f2e4853bd0cede07ab8853024c2e5050bb35", kill_on_drop: false }`
[INFO] [stdout] 5d057a0c809993f2b173dfe5cf31f2e4853bd0cede07ab8853024c2e5050bb35
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+32cd9114712a24010b0583624dc52ac302194128" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 46363896950bb98285e52af681edfe196ae94c662578c86f343220813c026cf8
[INFO] running `Command { std: "docker" "start" "-a" "46363896950bb98285e52af681edfe196ae94c662578c86f343220813c026cf8", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-programming-language v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::thread::Thread`
[INFO] [stdout]  --> src/chapter20/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::thread::Thread;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::Thread`
[INFO] [stdout]  --> src/chapter20/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::thread::Thread;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/chapter16/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Result as IoResult`
[INFO] [stdout]  --> src/chapter7/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io::Result as IoResult;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `cmp::Ordering` and `io`
[INFO] [stdout]  --> src/chapter7/main.rs:9:11
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::{cmp::Ordering, io};
[INFO] [stdout]   |           ^^^^^^^^^^^^^  ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user3`
[INFO] [stdout]   --> src/chapter5/main.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let user3 = User {
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user3`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::Result as IoResult`
[INFO] [stdout]  --> src/chapter7/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io::Result as IoResult;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `cmp::Ordering` and `io`
[INFO] [stdout]  --> src/chapter7/main.rs:9:11
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::{cmp::Ordering, io};
[INFO] [stdout]   |           ^^^^^^^^^^^^^  ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_5_1` is never used
[INFO] [stdout]  --> src/chapter5/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn practice_5_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `build_user` is never used
[INFO] [stdout]   --> src/chapter5/main.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `User` is never constructed
[INFO] [stdout]   --> src/chapter5/main.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: found module declaration for lib.rs
[INFO] [stdout]  --> src/chapter15/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | mod lib;
[INFO] [stdout]   | ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: lib.rs is the root of this crate's library target
[INFO] [stdout]   = help: to refer to it from other targets, use the library's name as the path
[INFO] [stdout]   = note: `#[warn(special_module_name)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/main.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let home = IpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         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: `x`
[INFO] [stdout]   --> src/chapter6/main.rs:21:13
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let x: i8 = 5;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/chapter6/main.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |         let y: Option<i8> = Some(5);
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_16_1` is never used
[INFO] [stdout]   --> src/chapter16/main.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn practice_16_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_16_2` is never used
[INFO] [stdout]   --> src/chapter16/main.rs:66:4
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn practice_16_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_6_1` is never used
[INFO] [stdout]  --> src/chapter6/main.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn practice_6_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `IpAddr` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:29:6
[INFO] [stdout]    |
[INFO] [stdout] 29 | enum IpAddr {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Message` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:35:6
[INFO] [stdout]    |
[INFO] [stdout] 35 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:43:8
[INFO] [stdout]    |
[INFO] [stdout] 42 | impl Message {
[INFO] [stdout]    | ------------ method in this implementation
[INFO] [stdout] 43 |     fn call(&self) {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_6_2` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:61:4
[INFO] [stdout]    |
[INFO] [stdout] 61 | fn practice_6_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Penny`, `Dime`, and `Quarter` are never constructed
[INFO] [stdout]    --> src/chapter6/main.rs:97:5
[INFO] [stdout]     |
[INFO] [stdout] 96  | enum Coin {
[INFO] [stdout]     |      ---- variants in this enum
[INFO] [stdout] 97  |     Penny,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 98  |     Nickel,
[INFO] [stdout] 99  |     Dime,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 100 |     Quarter(UsState),
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `value_in_cents` is never used
[INFO] [stdout]    --> src/chapter6/main.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn value_in_cents(coin: Coin) -> u32 {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Alabama` and `Alaska` are never constructed
[INFO] [stdout]    --> src/chapter6/main.rs:117:5
[INFO] [stdout]     |
[INFO] [stdout] 116 | enum UsState {
[INFO] [stdout]     |      ------- variants in this enum
[INFO] [stdout] 117 |     Alabama,
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 118 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `plus_one` is never used
[INFO] [stdout]    --> src/chapter6/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn plus_one(x: Option<i32>) -> Option<i32> {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/chapter4/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let s2 = s1;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapter4/main.rs:71:13
[INFO] [stdout]    |
[INFO] [stdout] 71 |         let r1 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapter4/main.rs:87:13
[INFO] [stdout]    |
[INFO] [stdout] 87 |         let r1 = &s; // 問題なし
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> src/chapter4/main.rs:88:13
[INFO] [stdout]    |
[INFO] [stdout] 88 |         let r2 = &s; // 問題なし
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r3`
[INFO] [stdout]   --> src/chapter4/main.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |         let r3 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]    --> src/chapter4/main.rs:100:13
[INFO] [stdout]     |
[INFO] [stdout] 100 |         let reference_to_nothing = no_dangle();
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_to_nothing`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_4_1` is never used
[INFO] [stdout]  --> src/chapter4/main.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn practice_4_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length_4_1` is never used
[INFO] [stdout]   --> src/chapter4/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn calculate_length_4_1(s: String) -> (String, usize) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_4_2` is never used
[INFO] [stdout]   --> src/chapter4/main.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn practice_4_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length_4_2` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:109:4
[INFO] [stdout]     |
[INFO] [stdout] 109 | fn calculate_length_4_2(s: &String) -> usize {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `change` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:113:4
[INFO] [stdout]     |
[INFO] [stdout] 113 | fn change(some_string: &mut String) {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `no_dangle` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:125:4
[INFO] [stdout]     |
[INFO] [stdout] 125 | fn no_dangle() -> String {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_1` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn practice_15_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:37:6
[INFO] [stdout]    |
[INFO] [stdout] 37 | enum List {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_2` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn practice_15_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]   --> src/chapter15/main.rs:81:8
[INFO] [stdout]    |
[INFO] [stdout] 81 | struct MyBox<T>(T);
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:84:8
[INFO] [stdout]    |
[INFO] [stdout] 83 | impl<T> MyBox<T> {
[INFO] [stdout]    | ---------------- associated function in this implementation
[INFO] [stdout] 84 |     fn new(x: T) -> MyBox<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `hello` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:97:4
[INFO] [stdout]    |
[INFO] [stdout] 97 | fn hello(name: &str) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_3` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn practice_15_3() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `CustomSmartPointer` is never constructed
[INFO] [stdout]    --> src/chapter15/main.rs:121:8
[INFO] [stdout]     |
[INFO] [stdout] 121 | struct CustomSmartPointer {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_4` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:132:4
[INFO] [stdout]     |
[INFO] [stdout] 132 | fn practice_15_4() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_5` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:159:4
[INFO] [stdout]     |
[INFO] [stdout] 159 | fn practice_15_5() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `value` and `children` are never read
[INFO] [stdout]    --> src/chapter15/main.rs:232:5
[INFO] [stdout]     |
[INFO] [stdout] 231 | struct Node {
[INFO] [stdout]     |        ---- fields in this struct
[INFO] [stdout] 232 |     value: i32,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 233 |     parent: RefCell<Weak<Node>>,
[INFO] [stdout] 234 |     children: RefCell<Vec<Rc<Node>>>,
[INFO] [stdout]     |     ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Node` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/chapter15/lib.rs:13:27
[INFO] [stdout]    |
[INFO] [stdout] 13 |     pub fn new(messenger: &T, max: usize) -> LimitTracker<T> {
[INFO] [stdout]    |                           ^^                 --------------- the lifetime gets resolved as `'_`
[INFO] [stdout]    |                           |
[INFO] [stdout]    |                           this lifetime flows to the output
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]    |
[INFO] [stdout] 13 |     pub fn new(messenger: &T, max: usize) -> LimitTracker<'_, T> {
[INFO] [stdout]    |                                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `format`
[INFO] [stdout]  --> src/chapter10/main.rs:1:16
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::fmt::{format, Debug, Display};
[INFO] [stdout]   |                ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: found module declaration for lib.rs
[INFO] [stdout]  --> src/chapter15/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | mod lib;
[INFO] [stdout]   | ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: lib.rs is the root of this crate's library target
[INFO] [stdout]   = help: to refer to it from other targets, use the library's name as the path
[INFO] [stdout]   = note: `#[warn(special_module_name)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/chapter8/main.rs:12:13
[INFO] [stdout]    |
[INFO] [stdout] 12 |         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: `row`
[INFO] [stdout]   --> src/chapter8/main.rs:81:13
[INFO] [stdout]    |
[INFO] [stdout] 81 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapter8/main.rs:93:13
[INFO] [stdout]    |
[INFO] [stdout] 93 |         let s = data.to_string();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapter8/main.rs:94:13
[INFO] [stdout]    |
[INFO] [stdout] 94 |         let s = String::from("initial contents");
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/chapter8/main.rs:145:13
[INFO] [stdout]     |
[INFO] [stdout] 145 |         let mut scores: HashMap<_, _> =
[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: function `practice_8_1` is never used
[INFO] [stdout]  --> src/chapter8/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_8_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_8_2` is never used
[INFO] [stdout]   --> src/chapter8/main.rs:89:4
[INFO] [stdout]    |
[INFO] [stdout] 89 | fn practice_8_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `point`
[INFO] [stdout]   --> src/chapter10/main.rs:12:13
[INFO] [stdout]    |
[INFO] [stdout] 12 |         let point = Point { x: 5, y: 10 };
[INFO] [stdout]    |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_point`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `point`
[INFO] [stdout]   --> src/chapter10/main.rs:13:13
[INFO] [stdout]    |
[INFO] [stdout] 13 |         let point = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]    |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_point`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_1` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn practice_15_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:37:6
[INFO] [stdout]    |
[INFO] [stdout] 37 | enum List {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_2` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn practice_15_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]   --> src/chapter15/main.rs:81:8
[INFO] [stdout]    |
[INFO] [stdout] 81 | struct MyBox<T>(T);
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:84:8
[INFO] [stdout]    |
[INFO] [stdout] 83 | impl<T> MyBox<T> {
[INFO] [stdout]    | ---------------- associated function in this implementation
[INFO] [stdout] 84 |     fn new(x: T) -> MyBox<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `hello` is never used
[INFO] [stdout]   --> src/chapter15/main.rs:97:4
[INFO] [stdout]    |
[INFO] [stdout] 97 | fn hello(name: &str) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_3` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn practice_15_3() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `CustomSmartPointer` is never constructed
[INFO] [stdout]    --> src/chapter15/main.rs:121:8
[INFO] [stdout]     |
[INFO] [stdout] 121 | struct CustomSmartPointer {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_4` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:132:4
[INFO] [stdout]     |
[INFO] [stdout] 132 | fn practice_15_4() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_15_5` is never used
[INFO] [stdout]    --> src/chapter15/main.rs:159:4
[INFO] [stdout]     |
[INFO] [stdout] 159 | fn practice_15_5() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `value` and `children` are never read
[INFO] [stdout]    --> src/chapter15/main.rs:232:5
[INFO] [stdout]     |
[INFO] [stdout] 231 | struct Node {
[INFO] [stdout]     |        ---- fields in this struct
[INFO] [stdout] 232 |     value: i32,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 233 |     parent: RefCell<Weak<Node>>,
[INFO] [stdout] 234 |     children: RefCell<Vec<Rc<Node>>>,
[INFO] [stdout]     |     ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `Node` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Messenger` is never used
[INFO] [stdout]  --> src/chapter15/lib.rs:1:11
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait Messenger {
[INFO] [stdout]   |           ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `LimitTracker` is never constructed
[INFO] [stdout]  --> src/chapter15/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct LimitTracker<'a, T: 'a + Messenger> {
[INFO] [stdout]   |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `set_value` are never used
[INFO] [stdout]   --> src/chapter15/lib.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 11 | / impl<'a, T> LimitTracker<'a, T>
[INFO] [stdout] 12 | | where T: Messenger {
[INFO] [stdout]    | |__________________- associated items in this implementation
[INFO] [stdout] 13 |       pub fn new(messenger: &T, max: usize) -> LimitTracker<T> {
[INFO] [stdout]    |              ^^^
[INFO] [stdout] ...
[INFO] [stdout] 21 |       pub fn set_value(&mut self, value: usize) {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/chapter15/lib.rs:13:27
[INFO] [stdout]    |
[INFO] [stdout] 13 |     pub fn new(messenger: &T, max: usize) -> LimitTracker<T> {
[INFO] [stdout]    |                           ^^                 --------------- the lifetime gets resolved as `'_`
[INFO] [stdout]    |                           |
[INFO] [stdout]    |                           this lifetime flows to the output
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]    |
[INFO] [stdout] 13 |     pub fn new(messenger: &T, max: usize) -> LimitTracker<'_, T> {
[INFO] [stdout]    |                                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item1`
[INFO] [stdout]    --> src/chapter10/main.rs:118:35
[INFO] [stdout]     |
[INFO] [stdout] 118 | pub fn notify_complex<T: Summary>(item1: &T, item2: &T) {
[INFO] [stdout]     |                                   ^^^^^ help: if this is intentional, prefix it with an underscore: `_item1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/chapter4/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let s2 = s1;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapter4/main.rs:71:13
[INFO] [stdout]    |
[INFO] [stdout] 71 |         let r1 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapter4/main.rs:87:13
[INFO] [stdout]    |
[INFO] [stdout] 87 |         let r1 = &s; // 問題なし
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> src/chapter4/main.rs:88:13
[INFO] [stdout]    |
[INFO] [stdout] 88 |         let r2 = &s; // 問題なし
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r3`
[INFO] [stdout]   --> src/chapter4/main.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |         let r3 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]    --> src/chapter4/main.rs:100:13
[INFO] [stdout]     |
[INFO] [stdout] 100 |         let reference_to_nothing = no_dangle();
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_to_nothing`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_4_1` is never used
[INFO] [stdout]  --> src/chapter4/main.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn practice_4_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length_4_1` is never used
[INFO] [stdout]   --> src/chapter4/main.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn calculate_length_4_1(s: String) -> (String, usize) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item2`
[INFO] [stdout]    --> src/chapter10/main.rs:118:46
[INFO] [stdout]     |
[INFO] [stdout] 118 | pub fn notify_complex<T: Summary>(item1: &T, item2: &T) {
[INFO] [stdout]     |                                              ^^^^^ help: if this is intentional, prefix it with an underscore: `_item2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `format`
[INFO] [stdout]  --> src/chapter10/main.rs:1:16
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::fmt::{format, Debug, Display};
[INFO] [stdout]   |                ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_4_2` is never used
[INFO] [stdout]   --> src/chapter4/main.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn practice_4_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length_4_2` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:109:4
[INFO] [stdout]     |
[INFO] [stdout] 109 | fn calculate_length_4_2(s: &String) -> usize {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `change` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:113:4
[INFO] [stdout]     |
[INFO] [stdout] 113 | fn change(some_string: &mut String) {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `no_dangle` is never used
[INFO] [stdout]    --> src/chapter4/main.rs:125:4
[INFO] [stdout]     |
[INFO] [stdout] 125 | fn no_dangle() -> String {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/chapter10/main.rs:122:24
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |                        ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/chapter10/main.rs:122:31
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |                               ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `result` is assigned to, but never used
[INFO] [stdout]    --> src/chapter10/main.rs:175:13
[INFO] [stdout]     |
[INFO] [stdout] 175 |         let result;
[INFO] [stdout]     |             ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_result` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `result` is never read
[INFO] [stdout]    --> src/chapter10/main.rs:178:13
[INFO] [stdout]     |
[INFO] [stdout] 178 |             result = longest(string1.as_str(), string2.as_str());
[INFO] [stdout]     |             ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `point`
[INFO] [stdout]   --> src/chapter10/main.rs:12:13
[INFO] [stdout]    |
[INFO] [stdout] 12 |         let point = Point { x: 5, y: 10 };
[INFO] [stdout]    |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_point`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `point`
[INFO] [stdout]   --> src/chapter10/main.rs:13:13
[INFO] [stdout]    |
[INFO] [stdout] 13 |         let point = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]    |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_point`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_10_1` is never used
[INFO] [stdout]  --> src/chapter10/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_10_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Point` is never constructed
[INFO] [stdout]   --> src/chapter10/main.rs:26:8
[INFO] [stdout]    |
[INFO] [stdout] 26 | struct Point<T> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `x` is never used
[INFO] [stdout]   --> src/chapter10/main.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 31 | impl <T> Point<T> {
[INFO] [stdout]    | ----------------- method in this implementation
[INFO] [stdout] 32 |     fn x(&self) -> &T {
[INFO] [stdout]    |        ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_10_2` is never used
[INFO] [stdout]   --> src/chapter10/main.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn practice_10_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `some_function` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Pair` is never constructed
[INFO] [stdout]    --> src/chapter10/main.rs:127:8
[INFO] [stdout]     |
[INFO] [stdout] 127 | struct Pair<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:133:8
[INFO] [stdout]     |
[INFO] [stdout] 132 | impl <T> Pair<T> {
[INFO] [stdout]     | ---------------- associated function in this implementation
[INFO] [stdout] 133 |     fn new(x: T, y: T) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `cmp_display` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:140:8
[INFO] [stdout]     |
[INFO] [stdout] 139 | impl <T: PartialOrd + Display> Pair<T> {
[INFO] [stdout]     | -------------------------------------- method in this implementation
[INFO] [stdout] 140 |     fn cmp_display(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item1`
[INFO] [stdout]    --> src/chapter10/main.rs:118:35
[INFO] [stdout]     |
[INFO] [stdout] 118 | pub fn notify_complex<T: Summary>(item1: &T, item2: &T) {
[INFO] [stdout]     |                                   ^^^^^ help: if this is intentional, prefix it with an underscore: `_item1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item2`
[INFO] [stdout]    --> src/chapter10/main.rs:118:46
[INFO] [stdout]     |
[INFO] [stdout] 118 | pub fn notify_complex<T: Summary>(item1: &T, item2: &T) {
[INFO] [stdout]     |                                              ^^^^^ help: if this is intentional, prefix it with an underscore: `_item2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/chapter10/main.rs:122:24
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |                        ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/chapter10/main.rs:122:31
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |                               ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/chapter3/main.rs:43:13
[INFO] [stdout]    |
[INFO] [stdout] 43 |         let spaces = spaces.len();
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `result` is assigned to, but never used
[INFO] [stdout]    --> src/chapter10/main.rs:175:13
[INFO] [stdout]     |
[INFO] [stdout] 175 |         let result;
[INFO] [stdout]     |             ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_result` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `result` is never read
[INFO] [stdout]    --> src/chapter10/main.rs:178:13
[INFO] [stdout]     |
[INFO] [stdout] 178 |             result = longest(string1.as_str(), string2.as_str());
[INFO] [stdout]     |             ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_10_1` is never used
[INFO] [stdout]  --> src/chapter10/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_10_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/chapter3/main.rs:78:14
[INFO] [stdout]    |
[INFO] [stdout] 78 |         let (x, y, z) = tup;
[INFO] [stdout]    |              ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/chapter3/main.rs:78:20
[INFO] [stdout]    |
[INFO] [stdout] 78 |         let (x, y, z) = tup;
[INFO] [stdout]    |                    ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Point` is never constructed
[INFO] [stdout]   --> src/chapter10/main.rs:26:8
[INFO] [stdout]    |
[INFO] [stdout] 26 | struct Point<T> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `x` is never used
[INFO] [stdout]   --> src/chapter10/main.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 31 | impl <T> Point<T> {
[INFO] [stdout]    | ----------------- method in this implementation
[INFO] [stdout] 32 |     fn x(&self) -> &T {
[INFO] [stdout]    |        ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_10_2` is never used
[INFO] [stdout]   --> src/chapter10/main.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn practice_10_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `some_function` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn some_function<T, U>(t: &T, u: &U) -> i32 where T: Display + Clone, U: Clone + Debug
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Pair` is never constructed
[INFO] [stdout]    --> src/chapter10/main.rs:127:8
[INFO] [stdout]     |
[INFO] [stdout] 127 | struct Pair<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:133:8
[INFO] [stdout]     |
[INFO] [stdout] 132 | impl <T> Pair<T> {
[INFO] [stdout]     | ---------------- associated function in this implementation
[INFO] [stdout] 133 |     fn new(x: T, y: T) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `cmp_display` is never used
[INFO] [stdout]    --> src/chapter10/main.rs:140:8
[INFO] [stdout]     |
[INFO] [stdout] 139 | impl <T: PartialOrd + Display> Pair<T> {
[INFO] [stdout]     | -------------------------------------- method in this implementation
[INFO] [stdout] 140 |     fn cmp_display(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/chapter3/main.rs:123:13
[INFO] [stdout]     |
[INFO] [stdout] 123 |         let y = 6;
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_POINTS` is never used
[INFO] [stdout]  --> src/chapter3/main.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | const MAX_POINTS: u32 = 100_000;
[INFO] [stdout]   |       ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_1` is never used
[INFO] [stdout]   --> src/chapter3/main.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn practice_3_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_2` is never used
[INFO] [stdout]   --> src/chapter3/main.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn practice_3_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_3` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:113:4
[INFO] [stdout]     |
[INFO] [stdout] 113 | fn practice_3_3() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_labeled_measurement` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:141:4
[INFO] [stdout]     |
[INFO] [stdout] 141 | fn print_labeled_measurement(value: i32, unit_label: char) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `plus_one` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn plus_one(x: i32) -> i32 {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user3`
[INFO] [stdout]   --> src/chapter5/main.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let user3 = User {
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user3`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_5_1` is never used
[INFO] [stdout]  --> src/chapter5/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn practice_5_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `build_user` is never used
[INFO] [stdout]   --> src/chapter5/main.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `User` is never constructed
[INFO] [stdout]   --> src/chapter5/main.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/chapter16/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Error`
[INFO] [stdout]  --> src/chapter9/main.rs:2:15
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io::{Error, Read};
[INFO] [stdout]   |               ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Error`
[INFO] [stdout]  --> src/chapter9/main.rs:2:15
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io::{Error, Read};
[INFO] [stdout]   |               ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/chapter8/main.rs:12:13
[INFO] [stdout]    |
[INFO] [stdout] 12 |         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: `row`
[INFO] [stdout]   --> src/chapter8/main.rs:81:13
[INFO] [stdout]    |
[INFO] [stdout] 81 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_9_1` is never used
[INFO] [stdout]  --> src/chapter9/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_9_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapter8/main.rs:93:13
[INFO] [stdout]    |
[INFO] [stdout] 93 |         let s = data.to_string();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapter8/main.rs:94:13
[INFO] [stdout]    |
[INFO] [stdout] 94 |         let s = String::from("initial contents");
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_9_1` is never used
[INFO] [stdout]  --> src/chapter9/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_9_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/chapter8/main.rs:145:13
[INFO] [stdout]     |
[INFO] [stdout] 145 |         let mut scores: HashMap<_, _> =
[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: function `practice_8_1` is never used
[INFO] [stdout]  --> src/chapter8/main.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn practice_8_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_8_2` is never used
[INFO] [stdout]   --> src/chapter8/main.rs:89:4
[INFO] [stdout]    |
[INFO] [stdout] 89 | fn practice_8_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_16_1` is never used
[INFO] [stdout]   --> src/chapter16/main.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn practice_16_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_16_2` is never used
[INFO] [stdout]   --> src/chapter16/main.rs:66:4
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn practice_16_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/chapter3/main.rs:43:13
[INFO] [stdout]    |
[INFO] [stdout] 43 |         let spaces = spaces.len();
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/chapter3/main.rs:78:14
[INFO] [stdout]    |
[INFO] [stdout] 78 |         let (x, y, z) = tup;
[INFO] [stdout]    |              ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/chapter3/main.rs:78:20
[INFO] [stdout]    |
[INFO] [stdout] 78 |         let (x, y, z) = tup;
[INFO] [stdout]    |                    ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/chapter3/main.rs:123:13
[INFO] [stdout]     |
[INFO] [stdout] 123 |         let y = 6;
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_POINTS` is never used
[INFO] [stdout]  --> src/chapter3/main.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | const MAX_POINTS: u32 = 100_000;
[INFO] [stdout]   |       ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_1` is never used
[INFO] [stdout]   --> src/chapter3/main.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn practice_3_1() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_2` is never used
[INFO] [stdout]   --> src/chapter3/main.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn practice_3_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_3_3` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:113:4
[INFO] [stdout]     |
[INFO] [stdout] 113 | fn practice_3_3() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_labeled_measurement` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:141:4
[INFO] [stdout]     |
[INFO] [stdout] 141 | fn print_labeled_measurement(value: i32, unit_label: char) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `plus_one` is never used
[INFO] [stdout]    --> src/chapter3/main.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn plus_one(x: i32) -> i32 {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/chapter6/main.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let home = IpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/chapter6/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         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: `x`
[INFO] [stdout]   --> src/chapter6/main.rs:21:13
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let x: i8 = 5;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/chapter6/main.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |         let y: Option<i8> = Some(5);
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_6_1` is never used
[INFO] [stdout]  --> src/chapter6/main.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn practice_6_1() {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `IpAddr` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:29:6
[INFO] [stdout]    |
[INFO] [stdout] 29 | enum IpAddr {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Message` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:35:6
[INFO] [stdout]    |
[INFO] [stdout] 35 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:43:8
[INFO] [stdout]    |
[INFO] [stdout] 42 | impl Message {
[INFO] [stdout]    | ------------ method in this implementation
[INFO] [stdout] 43 |     fn call(&self) {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `practice_6_2` is never used
[INFO] [stdout]   --> src/chapter6/main.rs:61:4
[INFO] [stdout]    |
[INFO] [stdout] 61 | fn practice_6_2() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Penny`, `Dime`, and `Quarter` are never constructed
[INFO] [stdout]    --> src/chapter6/main.rs:97:5
[INFO] [stdout]     |
[INFO] [stdout] 96  | enum Coin {
[INFO] [stdout]     |      ---- variants in this enum
[INFO] [stdout] 97  |     Penny,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 98  |     Nickel,
[INFO] [stdout] 99  |     Dime,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 100 |     Quarter(UsState),
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `value_in_cents` is never used
[INFO] [stdout]    --> src/chapter6/main.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn value_in_cents(coin: Coin) -> u32 {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Alabama` and `Alaska` are never constructed
[INFO] [stdout]    --> src/chapter6/main.rs:117:5
[INFO] [stdout]     |
[INFO] [stdout] 116 | enum UsState {
[INFO] [stdout]     |      ------- variants in this enum
[INFO] [stdout] 117 |     Alabama,
[INFO] [stdout]     |     ^^^^^^^
[INFO] [stdout] 118 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `plus_one` is never used
[INFO] [stdout]    --> src/chapter6/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn plus_one(x: Option<i32>) -> Option<i32> {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.27s
[INFO] running `Command { std: "docker" "inspect" "46363896950bb98285e52af681edfe196ae94c662578c86f343220813c026cf8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "46363896950bb98285e52af681edfe196ae94c662578c86f343220813c026cf8", kill_on_drop: false }`
[INFO] [stdout] 46363896950bb98285e52af681edfe196ae94c662578c86f343220813c026cf8