[INFO] cloning repository https://github.com/UedaA0816/rust-learn
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/UedaA0816/rust-learn" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUedaA0816%2Frust-learn", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUedaA0816%2Frust-learn'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e96ed82193c74fe6e8af6ac523d09694b8d0335d
[INFO] checking UedaA0816/rust-learn against master#ab26b175979ee7b2cb3302dce204b99df96f7efb for pr-157696
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUedaA0816%2Frust-learn" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/UedaA0816/rust-learn
[INFO] finished tweaking git repo https://github.com/UedaA0816/rust-learn
[INFO] tweaked toml for git repo https://github.com/UedaA0816/rust-learn written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/UedaA0816/rust-learn on toolchain ab26b175979ee7b2cb3302dce204b99df96f7efb
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ab26b175979ee7b2cb3302dce204b99df96f7efb" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/UedaA0816/rust-learn 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" "+ab26b175979ee7b2cb3302dce204b99df96f7efb" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded getrandom v0.2.4
[INFO] [stderr]   Downloaded libc v0.2.112
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d
[INFO] running `Command { std: "docker" "start" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d" "/opt/rustwide/cargo-home/bin/cargo" "+ab26b175979ee7b2cb3302dce204b99df96f7efb" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-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" "-w" "/opt/rustwide/workdir" "--user" "0:0" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d" "/opt/rustwide/cargo-home/bin/cargo" "+ab26b175979ee7b2cb3302dce204b99df96f7efb" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.112
[INFO] [stderr]     Checking ppv-lite86 v0.2.16
[INFO] [stderr]     Checking getrandom v0.2.4
[INFO] [stderr]     Checking rand_core v0.6.3
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.4
[INFO] [stderr]     Checking rust-learn v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::io::ErrorKind`
[INFO] [stdout]  --> src/chapters/ch9_2.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io::ErrorKind;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::ErrorKind`
[INFO] [stdout]  --> src/chapters/ch9_2.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io::ErrorKind;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `guess`
[INFO] [stdout]  --> src/chapters/ch3_2.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let guess: u32 = "42".parse().expect("Not a number!");
[INFO] [stdout]   |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_guess`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]  --> src/chapters/ch3_2.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |   let x = 2.0; // f64
[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/chapters/ch3_2.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let y: f32 = 3.0; // f32
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sum`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let sum = 5 + 10;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_sum`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `difference`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let difference = 95.5 - 4.3;
[INFO] [stdout]    |       ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_difference`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `product`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:19:7
[INFO] [stdout]    |
[INFO] [stdout] 19 |   let product = 4 * 30;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_product`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `quotient`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let quotient = 56.7 / 32.2;
[INFO] [stdout]    |       ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_quotient`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `floored`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let floored = 2 / 3; // Results in 0
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_floored`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `remainder`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let remainder = 43 % 5;
[INFO] [stdout]    |       ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_remainder`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:29:7
[INFO] [stdout]    |
[INFO] [stdout] 29 |   let t = true;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let f: bool = false; // with explicit type annotation
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:34:7
[INFO] [stdout]    |
[INFO] [stdout] 34 |   let c = 'z';
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:35:7
[INFO] [stdout]    |
[INFO] [stdout] 35 |   let z = 'ℤ';
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `heart_eyed_cat`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:36:7
[INFO] [stdout]    |
[INFO] [stdout] 36 |   let heart_eyed_cat = '😻';
[INFO] [stdout]    |       ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_heart_eyed_cat`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `five_hundred`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:41:7
[INFO] [stdout]    |
[INFO] [stdout] 41 |   let five_hundred = tup.0;
[INFO] [stdout]    |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_five_hundred`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six_point_four`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:43:7
[INFO] [stdout]    |
[INFO] [stdout] 43 |   let six_point_four = tup.1;
[INFO] [stdout]    |       ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_six_point_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `one`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:45:7
[INFO] [stdout]    |
[INFO] [stdout] 45 |   let one = tup.2;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_one`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:48:7
[INFO] [stdout]    |
[INFO] [stdout] 48 |   let a = [1, 2, 3, 4, 5];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `months`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:50:7
[INFO] [stdout]    |
[INFO] [stdout] 50 |   let months = ["January", "February", "March", "April", "May", "June", "July","August", "September", "October", "November", "Decemb...
[INFO] [stdout]    |       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 |   let a: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]  --> src/chapters/ch3_3.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let y = 6;
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lucky_number`
[INFO] [stdout]  --> src/chapters/ch3_4.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let lucky_number = 7; // I’m feeling lucky today
[INFO] [stdout]   |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lucky_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lucky_number`
[INFO] [stdout]   --> src/chapters/ch3_4.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let lucky_number = 7;
[INFO] [stdout]    |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lucky_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let s = "hello";
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let y = x;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:33:7
[INFO] [stdout]    |
[INFO] [stdout] 33 |   let s2 = s1.clone();
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let s1 = gives_ownership();         // gives_ownership moves its return
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:42:7
[INFO] [stdout]    |
[INFO] [stdout] 42 |   let s3 = takes_and_gives_back(s2);  // s2 is moved into
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/chapters/ch4_2.rs:36:7
[INFO] [stdout]    |
[INFO] [stdout] 36 |   let mut s = String::from("hello");
[INFO] [stdout]    |       ----^
[INFO] [stdout]    |       |
[INFO] [stdout]    |       help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:20:7
[INFO] [stdout]    |
[INFO] [stdout] 20 |   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: `r2`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:21:7
[INFO] [stdout]    |
[INFO] [stdout] 21 |   let r2 = &mut s;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     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: `r2`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:33:7
[INFO] [stdout]    |
[INFO] [stdout] 33 |   let r2 = &mut s;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let r1 = &s; // no problem
[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/chapters/ch4_2.rs:39:7
[INFO] [stdout]    |
[INFO] [stdout] 39 |   let r2 = &s; // no problem
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/chapters/ch4_3.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let mut text2 = String::from("hello_world");
[INFO] [stdout]    |       ----^^^^^
[INFO] [stdout]    |       |
[INFO] [stdout]    |       help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> src/chapters/ch4_3.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let slice = &s[0..2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> src/chapters/ch4_3.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let slice = &s[..2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user1`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let user1 = User {
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_user1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user3`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:24:7
[INFO] [stdout]    |
[INFO] [stdout] 24 |   let user3 = User {
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_user3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let black = Color(0, 0, 0);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:32:7
[INFO] [stdout]    |
[INFO] [stdout] 32 |   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: `rect4`
[INFO] [stdout]   --> src/chapters/ch5_3.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let rect4 = Rectangle::square(100);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_rect4`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:43:7
[INFO] [stdout]    |
[INFO] [stdout] 43 |   let four = IpAddrKind::V4;
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:44:7
[INFO] [stdout]    |
[INFO] [stdout] 44 |   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/chapters/ch6_1.rs:47:7
[INFO] [stdout]    |
[INFO] [stdout] 47 |   let home = IpAddr {
[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/chapters/ch6_1.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 |   let loopback = IpAddr {
[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/chapters/ch6_1.rs:58:7
[INFO] [stdout]    |
[INFO] [stdout] 58 |   let home = IpAddr2::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/chapters/ch6_1.rs:60:7
[INFO] [stdout]    |
[INFO] [stdout] 60 |   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: unused variable: `home`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:63:7
[INFO] [stdout]    |
[INFO] [stdout] 63 |   let home = IpAddr3::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/chapters/ch6_1.rs:65:7
[INFO] [stdout]    |
[INFO] [stdout] 65 |   let loopback = IpAddr3::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: `some_number`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:68:7
[INFO] [stdout]    |
[INFO] [stdout] 68 |   let some_number = Some(5);
[INFO] [stdout]    |       ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_string`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:69:7
[INFO] [stdout]    |
[INFO] [stdout] 69 |   let some_string = Some("a string");
[INFO] [stdout]    |       ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_string`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:71:7
[INFO] [stdout]    |
[INFO] [stdout] 71 |   let absent_number: Option<i32> = None;
[INFO] [stdout]    |       ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_absent_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cents`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:18:7
[INFO] [stdout]    |
[INFO] [stdout] 18 |   let cents = value_in_cents(Coin::Quarter(UsState::Alabama));
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_cents`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let six = plus_one(five);
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `guess`
[INFO] [stdout]  --> src/chapters/ch3_2.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let guess: u32 = "42".parse().expect("Not a number!");
[INFO] [stdout]   |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_guess`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]  --> src/chapters/ch3_2.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |   let x = 2.0; // f64
[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/chapters/ch3_2.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let y: f32 = 3.0; // f32
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sum`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let sum = 5 + 10;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_sum`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `difference`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let difference = 95.5 - 4.3;
[INFO] [stdout]    |       ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_difference`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `product`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:19:7
[INFO] [stdout]    |
[INFO] [stdout] 19 |   let product = 4 * 30;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_product`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `quotient`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let quotient = 56.7 / 32.2;
[INFO] [stdout]    |       ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_quotient`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `floored`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let floored = 2 / 3; // Results in 0
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_floored`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `remainder`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let remainder = 43 % 5;
[INFO] [stdout]    |       ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_remainder`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:29:7
[INFO] [stdout]    |
[INFO] [stdout] 29 |   let t = true;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let f: bool = false; // with explicit type annotation
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:34:7
[INFO] [stdout]    |
[INFO] [stdout] 34 |   let c = 'z';
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:35:7
[INFO] [stdout]    |
[INFO] [stdout] 35 |   let z = 'ℤ';
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `heart_eyed_cat`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:36:7
[INFO] [stdout]    |
[INFO] [stdout] 36 |   let heart_eyed_cat = '😻';
[INFO] [stdout]    |       ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_heart_eyed_cat`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `five_hundred`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:41:7
[INFO] [stdout]    |
[INFO] [stdout] 41 |   let five_hundred = tup.0;
[INFO] [stdout]    |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_five_hundred`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six_point_four`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:43:7
[INFO] [stdout]    |
[INFO] [stdout] 43 |   let six_point_four = tup.1;
[INFO] [stdout]    |       ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_six_point_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `one`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:45:7
[INFO] [stdout]    |
[INFO] [stdout] 45 |   let one = tup.2;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_one`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:48:7
[INFO] [stdout]    |
[INFO] [stdout] 48 |   let a = [1, 2, 3, 4, 5];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `months`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:50:7
[INFO] [stdout]    |
[INFO] [stdout] 50 |   let months = ["January", "February", "March", "April", "May", "June", "July","August", "September", "October", "November", "Decemb...
[INFO] [stdout]    |       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/chapters/ch3_2.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 |   let a: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]  --> src/chapters/ch3_3.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let y = 6;
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lucky_number`
[INFO] [stdout]  --> src/chapters/ch3_4.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let lucky_number = 7; // I’m feeling lucky today
[INFO] [stdout]   |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lucky_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lucky_number`
[INFO] [stdout]   --> src/chapters/ch3_4.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let lucky_number = 7;
[INFO] [stdout]    |       ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lucky_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let none = plus_one(None);
[INFO] [stdout]    |       ^^^^
[INFO] [stdout]    |
[INFO] [stdout] help: you might have meant to pattern match on the similarly named variant `None`
[INFO] [stdout]    |
[INFO] [stdout] 23 -   let none = plus_one(None);
[INFO] [stdout] 23 +   let std::prelude::v1::None = plus_one(None);
[INFO] [stdout]    |
[INFO] [stdout] help: if this is intentional, prefix it with an underscore
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let _none = plus_one(None);
[INFO] [stdout]    |       +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let v = vec![1, 2, 3];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `third`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:21:7
[INFO] [stdout]    |
[INFO] [stdout] 21 |   let third: &i32 = &v[2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `third`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let third: Option<&i32> = v.get(2);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `SpreadsheetCell`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 |   if let Some(SpreadsheetCell) = third {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_SpreadsheetCell`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let s = "hello";
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let y = x;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:33:7
[INFO] [stdout]    |
[INFO] [stdout] 33 |   let s2 = s1.clone();
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let s1 = gives_ownership();         // gives_ownership moves its return
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/chapters/ch4_1.rs:42:7
[INFO] [stdout]    |
[INFO] [stdout] 42 |   let s3 = takes_and_gives_back(s2);  // s2 is moved into
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let s3 = s1 + &s2; // s1はムーブされ、もう使用できないことに注意
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let s = format!("{}-{}-{}", s1, s2, s3);
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `len`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let len = String::from("Hola").len();
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `len`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:29:7
[INFO] [stdout]    |
[INFO] [stdout] 29 |   let len = String::from("Здравствуйте").len();
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:34:7
[INFO] [stdout]    |
[INFO] [stdout] 34 |   let s = &hello[0..4];
[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/chapters/ch4_2.rs:36:7
[INFO] [stdout]    |
[INFO] [stdout] 36 |   let mut s = String::from("hello");
[INFO] [stdout]    |       ----^
[INFO] [stdout]    |       |
[INFO] [stdout]    |       help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:20:7
[INFO] [stdout]    |
[INFO] [stdout] 20 |   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: `r2`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:21:7
[INFO] [stdout]    |
[INFO] [stdout] 21 |   let r2 = &mut s;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     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: `r2`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:33:7
[INFO] [stdout]    |
[INFO] [stdout] 33 |   let r2 = &mut s;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/chapters/ch4_2.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let r1 = &s; // no problem
[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/chapters/ch4_2.rs:39:7
[INFO] [stdout]    |
[INFO] [stdout] 39 |   let r2 = &s; // no problem
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/chapters/ch4_3.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let mut text2 = String::from("hello_world");
[INFO] [stdout]    |       ----^^^^^
[INFO] [stdout]    |       |
[INFO] [stdout]    |       help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> src/chapters/ch4_3.rs:12:7
[INFO] [stdout]    |
[INFO] [stdout] 12 |   let slice = &s[0..2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> src/chapters/ch4_3.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let slice = &s[..2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user1`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   let user1 = User {
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_user1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user3`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:24:7
[INFO] [stdout]    |
[INFO] [stdout] 24 |   let user3 = User {
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_user3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `black`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let black = Color(0, 0, 0);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]   --> src/chapters/ch5_1.rs:32:7
[INFO] [stdout]    |
[INFO] [stdout] 32 |   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: `rect4`
[INFO] [stdout]   --> src/chapters/ch5_3.rs:38:7
[INFO] [stdout]    |
[INFO] [stdout] 38 |   let rect4 = Rectangle::square(100);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_rect4`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:43:7
[INFO] [stdout]    |
[INFO] [stdout] 43 |   let four = IpAddrKind::V4;
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:44:7
[INFO] [stdout]    |
[INFO] [stdout] 44 |   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/chapters/ch6_1.rs:47:7
[INFO] [stdout]    |
[INFO] [stdout] 47 |   let home = IpAddr {
[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/chapters/ch6_1.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 |   let loopback = IpAddr {
[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/chapters/ch6_1.rs:58:7
[INFO] [stdout]    |
[INFO] [stdout] 58 |   let home = IpAddr2::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/chapters/ch6_1.rs:60:7
[INFO] [stdout]    |
[INFO] [stdout] 60 |   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: unused variable: `home`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:63:7
[INFO] [stdout]    |
[INFO] [stdout] 63 |   let home = IpAddr3::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/chapters/ch6_1.rs:65:7
[INFO] [stdout]    |
[INFO] [stdout] 65 |   let loopback = IpAddr3::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: `some_number`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:68:7
[INFO] [stdout]    |
[INFO] [stdout] 68 |   let some_number = Some(5);
[INFO] [stdout]    |       ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_string`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:69:7
[INFO] [stdout]    |
[INFO] [stdout] 69 |   let some_string = Some("a string");
[INFO] [stdout]    |       ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_string`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]   --> src/chapters/ch6_1.rs:71:7
[INFO] [stdout]    |
[INFO] [stdout] 71 |   let absent_number: Option<i32> = None;
[INFO] [stdout]    |       ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_absent_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cents`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:18:7
[INFO] [stdout]    |
[INFO] [stdout] 18 |   let cents = value_in_cents(Coin::Quarter(UsState::Alabama));
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_cents`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let six = plus_one(five);
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `username`, `email`, `sign_in_count`, and `active` are never read
[INFO] [stdout]  --> src/chapters/ch5_1.rs:3:3
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct User {
[INFO] [stdout]   |        ---- fields in this struct
[INFO] [stdout] 3 |   username: String,
[INFO] [stdout]   |   ^^^^^^^^
[INFO] [stdout] 4 |   email: String,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 5 |   sign_in_count: u64,
[INFO] [stdout]   |   ^^^^^^^^^^^^^
[INFO] [stdout] 6 |   active: bool,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]  --> src/chapters/ch5_1.rs:9:14
[INFO] [stdout]   |
[INFO] [stdout] 9 | struct Color(i32, i32, i32);
[INFO] [stdout]   |        ----- ^^^  ^^^  ^^^
[INFO] [stdout]   |        |
[INFO] [stdout]   |        fields in this struct
[INFO] [stdout]   |
[INFO] [stdout]   = help: consider removing these fields
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]   --> src/chapters/ch5_1.rs:10:14
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct Point(i32, i32, i32);
[INFO] [stdout]    |        ----- ^^^  ^^^  ^^^
[INFO] [stdout]    |        |
[INFO] [stdout]    |        fields in this struct
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider removing these fields
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `kind` and `address` are never read
[INFO] [stdout]  --> src/chapters/ch6_1.rs:8:3
[INFO] [stdout]   |
[INFO] [stdout] 7 | struct IpAddr {
[INFO] [stdout]   |        ------ fields in this struct
[INFO] [stdout] 8 |   kind: IpAddrKind,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout] 9 |   address: String,
[INFO] [stdout]   |   ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/chapters/ch6_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let none = plus_one(None);
[INFO] [stdout]    |       ^^^^
[INFO] [stdout]    |
[INFO] [stdout] help: you might have meant to pattern match on the similarly named variant `None`
[INFO] [stdout]    |
[INFO] [stdout] 23 -   let none = plus_one(None);
[INFO] [stdout] 23 +   let std::prelude::v1::None = plus_one(None);
[INFO] [stdout]    |
[INFO] [stdout] help: if this is intentional, prefix it with an underscore
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let _none = plus_one(None);
[INFO] [stdout]    |       +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:14:6
[INFO] [stdout]    |
[INFO] [stdout] 14 |   V4(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 14 -   V4(String),
[INFO] [stdout] 14 +   V4(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:15:6
[INFO] [stdout]    |
[INFO] [stdout] 15 |   V6(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 15 -   V6(String),
[INFO] [stdout] 15 +   V6(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, `2`, and `3` are never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:19:6
[INFO] [stdout]    |
[INFO] [stdout] 19 |   V4(u8, u8, u8, u8),
[INFO] [stdout]    |   -- ^^  ^^  ^^  ^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   fields in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 19 -   V4(u8, u8, u8, u8),
[INFO] [stdout] 19 +   V4((), (), (), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 |   V6(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 20 -   V6(String),
[INFO] [stdout] 20 +   V6(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Message` is never used
[INFO] [stdout]   --> src/chapters/ch6_1.rs:24:6
[INFO] [stdout]    |
[INFO] [stdout] 24 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]   --> src/chapters/ch6_1.rs:32:6
[INFO] [stdout]    |
[INFO] [stdout] 31 | impl Message {
[INFO] [stdout]    | ------------ method in this implementation
[INFO] [stdout] 32 |   fn call(&self) {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Alaska` is never constructed
[INFO] [stdout]  --> src/chapters/ch6_2.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | enum UsState {
[INFO] [stdout]   |      ------- variant in this enum
[INFO] [stdout] 4 |     Alabama,
[INFO] [stdout] 5 |     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: variants `Penny`, `Nickel`, and `Dime` are never constructed
[INFO] [stdout]   --> src/chapters/ch6_2.rs:10:3
[INFO] [stdout]    |
[INFO] [stdout]  9 | enum Coin {
[INFO] [stdout]    |      ---- variants in this enum
[INFO] [stdout] 10 |   Penny,
[INFO] [stdout]    |   ^^^^^
[INFO] [stdout] 11 |   Nickel,
[INFO] [stdout]    |   ^^^^^^
[INFO] [stdout] 12 |   Dime,
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:3:7
[INFO] [stdout]   |
[INFO] [stdout] 3 |   Int(i32),
[INFO] [stdout]   |   --- ^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 3 -   Int(i32),
[INFO] [stdout] 3 +   Int(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |   Float(f64),
[INFO] [stdout]   |   ----- ^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 4 -   Float(f64),
[INFO] [stdout] 4 +   Float(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |   Text(String),
[INFO] [stdout]   |   ---- ^^^^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 5 -   Text(String),
[INFO] [stdout] 5 +   Text(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let v = vec![1, 2, 3];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `summarize_author` is never used
[INFO] [stdout]  --> src/chapters/ch10_2.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait Summary {
[INFO] [stdout]   |           ------- method in this trait
[INFO] [stdout] ...
[INFO] [stdout] 7 |   fn summarize_author(&self) -> String;
[INFO] [stdout]   |      ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `third`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:21:7
[INFO] [stdout]    |
[INFO] [stdout] 21 |   let third: &i32 = &v[2];
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `third`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 22 |   let third: Option<&i32> = v.get(2);
[INFO] [stdout]    |       ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `content` is never read
[INFO] [stdout]   --> src/chapters/ch10_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 18 | pub struct NewsArticle {
[INFO] [stdout]    |            ----------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 22 |   pub content: String,
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `SpreadsheetCell`
[INFO] [stdout]   --> src/chapters/ch8_1.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 |   if let Some(SpreadsheetCell) = third {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_SpreadsheetCell`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `reply` and `retweet` are never read
[INFO] [stdout]   --> src/chapters/ch10_2.rs:41:7
[INFO] [stdout]    |
[INFO] [stdout] 38 | pub struct Tweet {
[INFO] [stdout]    |            ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 41 |   pub reply: bool,
[INFO] [stdout]    |       ^^^^^
[INFO] [stdout] 42 |   pub retweet: bool,
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `notify_syntax_sugar` is never used
[INFO] [stdout]    --> src/chapters/ch10_2.rs:108:8
[INFO] [stdout]     |
[INFO] [stdout] 108 | pub fn notify_syntax_sugar<T: Summary>(item: &T) {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `notify_multi_trait` is never used
[INFO] [stdout]    --> src/chapters/ch10_2.rs:113:8
[INFO] [stdout]     |
[INFO] [stdout] 113 | pub fn notify_multi_trait(item: &(impl Summary + Display)) {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:16:7
[INFO] [stdout]    |
[INFO] [stdout] 16 |   let s3 = s1 + &s2; // s1はムーブされ、もう使用できないことに注意
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:23:7
[INFO] [stdout]    |
[INFO] [stdout] 23 |   let s = format!("{}-{}-{}", s1, s2, s3);
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `len`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let len = String::from("Hola").len();
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `len`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:29:7
[INFO] [stdout]    |
[INFO] [stdout] 29 |   let len = String::from("Здравствуйте").len();
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/chapters/ch8_2.rs:34:7
[INFO] [stdout]    |
[INFO] [stdout] 34 |   let s = &hello[0..4];
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `SpreadsheetCell` should have a snake case name
[INFO] [stdout]   --> src/chapters/ch8_1.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 |   if let Some(SpreadsheetCell) = third {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `spreadsheet_cell`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `username`, `email`, `sign_in_count`, and `active` are never read
[INFO] [stdout]  --> src/chapters/ch5_1.rs:3:3
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct User {
[INFO] [stdout]   |        ---- fields in this struct
[INFO] [stdout] 3 |   username: String,
[INFO] [stdout]   |   ^^^^^^^^
[INFO] [stdout] 4 |   email: String,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 5 |   sign_in_count: u64,
[INFO] [stdout]   |   ^^^^^^^^^^^^^
[INFO] [stdout] 6 |   active: bool,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]  --> src/chapters/ch5_1.rs:9:14
[INFO] [stdout]   |
[INFO] [stdout] 9 | struct Color(i32, i32, i32);
[INFO] [stdout]   |        ----- ^^^  ^^^  ^^^
[INFO] [stdout]   |        |
[INFO] [stdout]   |        fields in this struct
[INFO] [stdout]   |
[INFO] [stdout]   = help: consider removing these fields
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]   --> src/chapters/ch5_1.rs:10:14
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct Point(i32, i32, i32);
[INFO] [stdout]    |        ----- ^^^  ^^^  ^^^
[INFO] [stdout]    |        |
[INFO] [stdout]    |        fields in this struct
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider removing these fields
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `kind` and `address` are never read
[INFO] [stdout]  --> src/chapters/ch6_1.rs:8:3
[INFO] [stdout]   |
[INFO] [stdout] 7 | struct IpAddr {
[INFO] [stdout]   |        ------ fields in this struct
[INFO] [stdout] 8 |   kind: IpAddrKind,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout] 9 |   address: String,
[INFO] [stdout]   |   ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:14:6
[INFO] [stdout]    |
[INFO] [stdout] 14 |   V4(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 14 -   V4(String),
[INFO] [stdout] 14 +   V4(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:15:6
[INFO] [stdout]    |
[INFO] [stdout] 15 |   V6(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 15 -   V6(String),
[INFO] [stdout] 15 +   V6(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, `2`, and `3` are never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:19:6
[INFO] [stdout]    |
[INFO] [stdout] 19 |   V4(u8, u8, u8, u8),
[INFO] [stdout]    |   -- ^^  ^^  ^^  ^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   fields in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 19 -   V4(u8, u8, u8, u8),
[INFO] [stdout] 19 +   V4((), (), (), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/chapters/ch6_1.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 |   V6(String),
[INFO] [stdout]    |   -- ^^^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 20 -   V6(String),
[INFO] [stdout] 20 +   V6(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Message` is never used
[INFO] [stdout]   --> src/chapters/ch6_1.rs:24:6
[INFO] [stdout]    |
[INFO] [stdout] 24 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]   --> src/chapters/ch6_1.rs:32:6
[INFO] [stdout]    |
[INFO] [stdout] 31 | impl Message {
[INFO] [stdout]    | ------------ method in this implementation
[INFO] [stdout] 32 |   fn call(&self) {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Alaska` is never constructed
[INFO] [stdout]  --> src/chapters/ch6_2.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | enum UsState {
[INFO] [stdout]   |      ------- variant in this enum
[INFO] [stdout] 4 |     Alabama,
[INFO] [stdout] 5 |     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: variants `Penny`, `Nickel`, and `Dime` are never constructed
[INFO] [stdout]   --> src/chapters/ch6_2.rs:10:3
[INFO] [stdout]    |
[INFO] [stdout]  9 | enum Coin {
[INFO] [stdout]    |      ---- variants in this enum
[INFO] [stdout] 10 |   Penny,
[INFO] [stdout]    |   ^^^^^
[INFO] [stdout] 11 |   Nickel,
[INFO] [stdout]    |   ^^^^^^
[INFO] [stdout] 12 |   Dime,
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:3:7
[INFO] [stdout]   |
[INFO] [stdout] 3 |   Int(i32),
[INFO] [stdout]   |   --- ^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 3 -   Int(i32),
[INFO] [stdout] 3 +   Int(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |   Float(f64),
[INFO] [stdout]   |   ----- ^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 4 -   Float(f64),
[INFO] [stdout] 4 +   Float(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/chapters/ch8_1.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |   Text(String),
[INFO] [stdout]   |   ---- ^^^^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 5 -   Text(String),
[INFO] [stdout] 5 +   Text(()),
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `summarize_author` is never used
[INFO] [stdout]  --> src/chapters/ch10_2.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait Summary {
[INFO] [stdout]   |           ------- method in this trait
[INFO] [stdout] ...
[INFO] [stdout] 7 |   fn summarize_author(&self) -> String;
[INFO] [stdout]   |      ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `content` is never read
[INFO] [stdout]   --> src/chapters/ch10_2.rs:22:7
[INFO] [stdout]    |
[INFO] [stdout] 18 | pub struct NewsArticle {
[INFO] [stdout]    |            ----------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 22 |   pub content: String,
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `reply` and `retweet` are never read
[INFO] [stdout]   --> src/chapters/ch10_2.rs:41:7
[INFO] [stdout]    |
[INFO] [stdout] 38 | pub struct Tweet {
[INFO] [stdout]    |            ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 41 |   pub reply: bool,
[INFO] [stdout]    |       ^^^^^
[INFO] [stdout] 42 |   pub retweet: bool,
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `notify_syntax_sugar` is never used
[INFO] [stdout]    --> src/chapters/ch10_2.rs:108:8
[INFO] [stdout]     |
[INFO] [stdout] 108 | pub fn notify_syntax_sugar<T: Summary>(item: &T) {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `notify_multi_trait` is never used
[INFO] [stdout]    --> src/chapters/ch10_2.rs:113:8
[INFO] [stdout]     |
[INFO] [stdout] 113 | pub fn notify_multi_trait(item: &(impl Summary + Display)) {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `SpreadsheetCell` should have a snake case name
[INFO] [stdout]   --> src/chapters/ch8_1.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 |   if let Some(SpreadsheetCell) = third {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `spreadsheet_cell`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.44s
[INFO] running `Command { std: "docker" "inspect" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d", kill_on_drop: false }`
[INFO] [stdout] 9acd46c0ade2e3d87d794cbb00a39e076058230e092300313d63aa560f35a79d
