[INFO] cloning repository https://github.com/sqlnice/learning-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sqlnice/learning-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsqlnice%2Flearning-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsqlnice%2Flearning-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7d6897d80fff57d56f8507e27f3a84a438041e88
[INFO] building sqlnice/learning-rust against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsqlnice%2Flearning-rust" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sqlnice/learning-rust on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sqlnice/learning-rust
[INFO] finished tweaking git repo https://github.com/sqlnice/learning-rust
[INFO] tweaked toml for git repo https://github.com/sqlnice/learning-rust written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/sqlnice/learning-rust 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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e4cf95ca3570a6729c11c86965a49bf8655d4ff68f7fb54aafc697360021783a
[INFO] running `Command { std: "docker" "start" "-a" "e4cf95ca3570a6729c11c86965a49bf8655d4ff68f7fb54aafc697360021783a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e4cf95ca3570a6729c11c86965a49bf8655d4ff68f7fb54aafc697360021783a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e4cf95ca3570a6729c11c86965a49bf8655d4ff68f7fb54aafc697360021783a", kill_on_drop: false }`
[INFO] [stdout] e4cf95ca3570a6729c11c86965a49bf8655d4ff68f7fb54aafc697360021783a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 31c641287c4e20c318e34957ee3160f8a526b354d4f5d4dfcb7fc29eaf8e14e4
[INFO] running `Command { std: "docker" "start" "-a" "31c641287c4e20c318e34957ee3160f8a526b354d4f5d4dfcb7fc29eaf8e14e4", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling ppv-lite86 v0.2.17
[INFO] [stderr]    Compiling getrandom v0.2.8
[INFO] [stderr]    Compiling rand_core v0.6.4
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.5
[INFO] [stderr]    Compiling learning-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `order1`
[INFO] [stdout]   --> src/lib.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let order1 = back_of_house::Appetizer::Soup;
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_order1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `deliver_order` is never used
[INFO] [stdout]   --> src/lib.rs:16:4
[INFO] [stdout]    |
[INFO] [stdout] 16 | fn deliver_order() {}
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `eat_at_restaurant` is never used
[INFO] [stdout]   --> src/lib.rs:43:4
[INFO] [stdout]    |
[INFO] [stdout] 43 | fn eat_at_restaurant() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/lib.rs:56:8
[INFO] [stdout]    |
[INFO] [stdout] 56 | struct Rectangle {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `can_hold` is never used
[INFO] [stdout]   --> src/lib.rs:62:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | impl Rectangle {
[INFO] [stdout]    | -------------- method in this implementation
[INFO] [stdout] 62 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `add_to_waitlist` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn add_to_waitlist() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `seat_at_table` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn seat_at_table() {}
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 |     fn take_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `serve_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn serve_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_payment` is never used
[INFO] [stdout]  --> src/front_of_house.rs:6:8
[INFO] [stdout]   |
[INFO] [stdout] 6 |     fn take_payment() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Appetizer` is never used
[INFO] [stdout]   --> src/lib.rs:19:14
[INFO] [stdout]    |
[INFO] [stdout] 19 |     pub enum Appetizer {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `fix_incorrect_order` is never used
[INFO] [stdout]   --> src/lib.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn fix_incorrect_order() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `cook_order` is never used
[INFO] [stdout]   --> src/lib.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn cook_order() {}
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Breakfast` is never constructed
[INFO] [stdout]   --> src/lib.rs:29:16
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub struct Breakfast {
[INFO] [stdout]    |                ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `summer` is never used
[INFO] [stdout]   --> src/lib.rs:34:16
[INFO] [stdout]    |
[INFO] [stdout] 33 |     impl Breakfast {
[INFO] [stdout]    |     -------------- associated function in this implementation
[INFO] [stdout] 34 |         pub fn summer(toast: &str) -> Breakfast {
[INFO] [stdout]    |                ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::num`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use core::num;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `hash::Hash`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     hash::Hash,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Read`
[INFO] [stdout]   --> src/main.rs:12:27
[INFO] [stdout]    |
[INFO] [stdout] 12 |     io::{self, ErrorKind, Read},
[INFO] [stdout]    |                           ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `borrow::Borrow`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     borrow::Borrow,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]    --> src/main.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |     let c = 'z';
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]    --> src/main.rs:134:9
[INFO] [stdout]     |
[INFO] [stdout] 134 |     let z: char = '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/main.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     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/main.rs:144:9
[INFO] [stdout]     |
[INFO] [stdout] 144 |     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/main.rs:145:9
[INFO] [stdout]     |
[INFO] [stdout] 145 |     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/main.rs:146:9
[INFO] [stdout]     |
[INFO] [stdout] 146 |     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: `months`
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 |     let months: [&str; 12] = [
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `first`
[INFO] [stdout]    --> src/main.rs:163:9
[INFO] [stdout]     |
[INFO] [stdout] 163 |     let first = a[0]; // 使用索引访问
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_first`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:173:9
[INFO] [stdout]     |
[INFO] [stdout] 173 |     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: `number`
[INFO] [stdout]    --> src/main.rs:206:9
[INFO] [stdout]     |
[INFO] [stdout] 206 |     let number = if condition { 5 } else { 6 }; // 分支返回的类型必须相同
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:281:9
[INFO] [stdout]     |
[INFO] [stdout] 281 |     let s2 = s1;
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]    --> src/main.rs:330:9
[INFO] [stdout]     |
[INFO] [stdout] 330 |     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: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:344:9
[INFO] [stdout]     |
[INFO] [stdout] 344 |     let mut s = String::from("hello world");
[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: unused variable: `user3`
[INFO] [stdout]    --> src/main.rs:382:9
[INFO] [stdout]     |
[INFO] [stdout] 382 |     let user3: User = 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/main.rs:390:9
[INFO] [stdout]     |
[INFO] [stdout] 390 |     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: `subject`
[INFO] [stdout]    --> src/main.rs:394:9
[INFO] [stdout]     |
[INFO] [stdout] 394 |     let subject = AlwaysEqual;
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_subject`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]    --> src/main.rs:463:9
[INFO] [stdout]     |
[INFO] [stdout] 463 |     let four = IpAddrkind::V4(String::from("127.0.0.1"));
[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/main.rs:464:9
[INFO] [stdout]     |
[INFO] [stdout] 464 |     let six = IpAddrkind::V6(String::from("::1"));
[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/main.rs:469:9
[INFO] [stdout]     |
[INFO] [stdout] 469 |     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] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]    --> src/main.rs:470:9
[INFO] [stdout]     |
[INFO] [stdout] 470 |     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: `some_number`
[INFO] [stdout]    --> src/main.rs:498:9
[INFO] [stdout]     |
[INFO] [stdout] 498 |     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_char`
[INFO] [stdout]    --> src/main.rs:499:9
[INFO] [stdout]     |
[INFO] [stdout] 499 |     let some_char = Some('e');
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]    --> src/main.rs:500:9
[INFO] [stdout]     |
[INFO] [stdout] 500 |     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: `six`
[INFO] [stdout]    --> src/main.rs:545:9
[INFO] [stdout]     |
[INFO] [stdout] 545 |     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: `none`
[INFO] [stdout]    --> src/main.rs:546:9
[INFO] [stdout]     |
[INFO] [stdout] 546 |     let none = plus_one(None);
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]    --> src/main.rs:612:9
[INFO] [stdout]     |
[INFO] [stdout] 612 |     let v: Vec<i32> = Vec::new();
[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/main.rs:619:9
[INFO] [stdout]     |
[INFO] [stdout] 619 |     let third = &v[2];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]    --> src/main.rs:637:9
[INFO] [stdout]     |
[INFO] [stdout] 637 |     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/main.rs:648:9
[INFO] [stdout]     |
[INFO] [stdout] 648 |     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/main.rs:649:9
[INFO] [stdout]     |
[INFO] [stdout] 649 |     let s = "initial contents".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/main.rs:661:9
[INFO] [stdout]     |
[INFO] [stdout] 661 |     let s = format!("{s1}-{s2}");
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:664:9
[INFO] [stdout]     |
[INFO] [stdout] 664 |     let s1 = String::from("hello");
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/main.rs:669:9
[INFO] [stdout]     |
[INFO] [stdout] 669 |     let s = &hello[0..4]; // Зд 每个字母长度为 2 字节
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file_result`
[INFO] [stdout]    --> src/main.rs:735:9
[INFO] [stdout]     |
[INFO] [stdout] 735 |     let greeting_file_result = File::open("hello.txt");
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:750:9
[INFO] [stdout]     |
[INFO] [stdout] 750 |     let greeting_file = File::open("hello.txt").unwrap_or_else(|error| {
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:762:9
[INFO] [stdout]     |
[INFO] [stdout] 762 |     let greeting_file = File::open("hello.txt").unwrap();
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:764:9
[INFO] [stdout]     |
[INFO] [stdout] 764 |     let greeting_file =
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `integer`
[INFO] [stdout]    --> src/main.rs:834:9
[INFO] [stdout]     |
[INFO] [stdout] 834 |     let integer = Point { x: 5, y: 10 };
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `float`
[INFO] [stdout]    --> src/main.rs:835:9
[INFO] [stdout]     |
[INFO] [stdout] 835 |     let float = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:815:13
[INFO] [stdout]     |
[INFO] [stdout] 815 |         for item in list {
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:814:13
[INFO] [stdout]     |
[INFO] [stdout] 814 |         let mut largest = &list[0];
[INFO] [stdout]     |             ----^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:920:41
[INFO] [stdout]     |
[INFO] [stdout] 920 |     pub fn notify<T: Summary + Display>(item: &T) {}
[INFO] [stdout]     |                                         ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:923:28
[INFO] [stdout]     |
[INFO] [stdout] 923 |     fn some_function<T, U>(t: &T, u: &U)
[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/main.rs:923:35
[INFO] [stdout]     |
[INFO] [stdout] 923 |     fn some_function<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                                   ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]     --> src/main.rs:1002:9
[INFO] [stdout]      |
[INFO] [stdout] 1002 |     let i = ImportantExcerpt {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]     --> src/main.rs:1024:9
[INFO] [stdout]      |
[INFO] [stdout] 1024 |     let s: &'static str = "I have a static lifetime";
[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/main.rs:989:32
[INFO] [stdout]     |
[INFO] [stdout] 989 |     fn longest<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]     |                                ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]     --> src/main.rs:1112:9
[INFO] [stdout]      |
[INFO] [stdout] 1112 |     let s = example_closure("Hello".to_string());
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list`
[INFO] [stdout]     --> src/main.rs:1268:9
[INFO] [stdout]      |
[INFO] [stdout] 1268 |     let list = Cons(1, Box::new(Cons(2, Box::new(Cons(3, Box::new(Nil))))));
[INFO] [stdout]      |         ^^^^ help: if this is intentional, prefix it with an underscore: `_list`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]     --> src/main.rs:1321:9
[INFO] [stdout]      |
[INFO] [stdout] 1321 |     let c = CustomSmartPointer {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `d`
[INFO] [stdout]     --> src/main.rs:1324:9
[INFO] [stdout]      |
[INFO] [stdout] 1324 |     let d = CustomSmartPointer {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_d`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]     --> src/main.rs:1349:9
[INFO] [stdout]      |
[INFO] [stdout] 1349 |     let b = Cons(3, Rc::clone(&a)); // 不会拷贝, 只会操作引用计数从 1 -> 2
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]     --> src/main.rs:1352:13
[INFO] [stdout]      |
[INFO] [stdout] 1352 |         let c = Cons(4, Rc::clone(&a)); // 不会拷贝, 只会操作引用计数从 2 -> 3
[INFO] [stdout]      |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `post`
[INFO] [stdout]     --> src/main.rs:1785:31
[INFO] [stdout]      |
[INFO] [stdout] 1785 |         fn content<'a>(&self, post: &'a Post) -> &'a str {
[INFO] [stdout]      |                               ^^^^ help: if this is intentional, prefix it with an underscore: `_post`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1871:9
[INFO] [stdout]      |
[INFO] [stdout] 1871 |     let x = 5;
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1873:10
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[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/main.rs:1873:13
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[INFO] [stdout]      |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]     --> src/main.rs:1873:16
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[INFO] [stdout]      |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1876:12
[INFO] [stdout]      |
[INFO] [stdout] 1876 |     fn foo(x: i32) {}
[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/main.rs:2021:9
[INFO] [stdout]      |
[INFO] [stdout] 2021 |     let y = 10;
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]     --> src/main.rs:2167:9
[INFO] [stdout]      |
[INFO] [stdout] 2167 |     let f: Thunk = Box::new(|| println!("hi"));
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]     --> src/main.rs:2168:24
[INFO] [stdout]      |
[INFO] [stdout] 2168 |     fn takes_long_type(f: Thunk) {}
[INFO] [stdout]      |                        ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]     --> src/main.rs:2211:9
[INFO] [stdout]      |
[INFO] [stdout] 2211 |     let v: Vec<i32> = vec![1, 2, 3];
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `guess_number` is never used
[INFO] [stdout]   --> src/main.rs:64:4
[INFO] [stdout]    |
[INFO] [stdout] 64 | fn guess_number() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `variables_and_mutability` is never used
[INFO] [stdout]   --> src/main.rs:95:4
[INFO] [stdout]    |
[INFO] [stdout] 95 | fn variables_and_mutability() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `data_types` is never used
[INFO] [stdout]    --> src/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn data_types() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `another_function` is never used
[INFO] [stdout]    --> src/main.rs:166:4
[INFO] [stdout]     |
[INFO] [stdout] 166 | fn another_function(x: i32) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `control_flow` is never used
[INFO] [stdout]    --> src/main.rs:192:4
[INFO] [stdout]     |
[INFO] [stdout] 192 | fn control_flow() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `ownership` is never used
[INFO] [stdout]    --> src/main.rs:272:4
[INFO] [stdout]     |
[INFO] [stdout] 272 | fn ownership() {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `references_and_borrowing` is never used
[INFO] [stdout]    --> src/main.rs:312:4
[INFO] [stdout]     |
[INFO] [stdout] 312 | fn references_and_borrowing() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `slices` is never used
[INFO] [stdout]    --> src/main.rs:343:4
[INFO] [stdout]     |
[INFO] [stdout] 343 | fn slices() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_structs` is never used
[INFO] [stdout]    --> src/main.rs:359:4
[INFO] [stdout]     |
[INFO] [stdout] 359 | fn defining_structs() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `example_structs` is never used
[INFO] [stdout]    --> src/main.rs:397:4
[INFO] [stdout]     |
[INFO] [stdout] 397 | fn example_structs() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `method_syntax` is never used
[INFO] [stdout]    --> src/main.rs:417:4
[INFO] [stdout]     |
[INFO] [stdout] 417 | fn method_syntax() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `area` is never used
[INFO] [stdout]    --> src/main.rs:424:12
[INFO] [stdout]     |
[INFO] [stdout] 423 |     impl Rectangle {
[INFO] [stdout]     |     -------------- method in this implementation
[INFO] [stdout] 424 |         fn area(self: &Self) -> u32 {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `can_hold` and `square` are never used
[INFO] [stdout]    --> src/main.rs:429:12
[INFO] [stdout]     |
[INFO] [stdout] 428 |     impl Rectangle {
[INFO] [stdout]     |     -------------- associated items in this implementation
[INFO] [stdout] 429 |         fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 432 |         fn square(size: u32) -> Self {
[INFO] [stdout]     |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_an_enum` is never used
[INFO] [stdout]    --> src/main.rs:458:4
[INFO] [stdout]     |
[INFO] [stdout] 458 | fn defining_an_enum() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]    --> src/main.rs:490:12
[INFO] [stdout]     |
[INFO] [stdout] 489 |     impl Message {
[INFO] [stdout]     |     ------------ method in this implementation
[INFO] [stdout] 490 |         fn call(&self) {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `match_flow` is never used
[INFO] [stdout]    --> src/main.rs:505:4
[INFO] [stdout]     |
[INFO] [stdout] 505 | fn match_flow() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `if_let` is never used
[INFO] [stdout]    --> src/main.rs:564:4
[INFO] [stdout]     |
[INFO] [stdout] 564 | fn if_let() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_modules_to_control_scope_and_privacy` is never used
[INFO] [stdout]    --> src/main.rs:594:4
[INFO] [stdout]     |
[INFO] [stdout] 594 | fn defining_modules_to_control_scope_and_privacy() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `paths_for_referring_to_an_item_in_the_module_tree` is never used
[INFO] [stdout]    --> src/main.rs:599:4
[INFO] [stdout]     |
[INFO] [stdout] 599 | fn paths_for_referring_to_an_item_in_the_module_tree() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `vectors` is never used
[INFO] [stdout]    --> src/main.rs:611:4
[INFO] [stdout]     |
[INFO] [stdout] 611 | fn vectors() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strings` is never used
[INFO] [stdout]    --> src/main.rs:645:4
[INFO] [stdout]     |
[INFO] [stdout] 645 | fn strings() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `hash_maps` is never used
[INFO] [stdout]    --> src/main.rs:687:4
[INFO] [stdout]     |
[INFO] [stdout] 687 | fn hash_maps() {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `unrecoverable_errors_with_panic` is never used
[INFO] [stdout]    --> src/main.rs:728:4
[INFO] [stdout]     |
[INFO] [stdout] 728 | fn unrecoverable_errors_with_panic() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `recoverable_errors_with_result` is never used
[INFO] [stdout]    --> src/main.rs:734:4
[INFO] [stdout]     |
[INFO] [stdout] 734 | fn recoverable_errors_with_result() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `to_panic_or_not_to_panic` is never used
[INFO] [stdout]    --> src/main.rs:803:4
[INFO] [stdout]     |
[INFO] [stdout] 803 | fn to_panic_or_not_to_panic() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `syntax` is never used
[INFO] [stdout]    --> src/main.rs:811:4
[INFO] [stdout]     |
[INFO] [stdout] 811 | fn syntax() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `x` is never used
[INFO] [stdout]    --> src/main.rs:848:12
[INFO] [stdout]     |
[INFO] [stdout] 847 |     impl<T> Point<T> {
[INFO] [stdout]     |     ---------------- method in this implementation
[INFO] [stdout] 848 |         fn x(&self) -> &T {
[INFO] [stdout]     |            ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `distance_from_origin` is never used
[INFO] [stdout]    --> src/main.rs:857:12
[INFO] [stdout]     |
[INFO] [stdout] 856 |     impl Point<f32> {
[INFO] [stdout]     |     --------------- method in this implementation
[INFO] [stdout] 857 |         fn distance_from_origin(&self) -> f32 {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `traits` is never used
[INFO] [stdout]    --> src/main.rs:865:4
[INFO] [stdout]     |
[INFO] [stdout] 865 | fn traits() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `summarize` is never used
[INFO] [stdout]    --> src/main.rs:869:12
[INFO] [stdout]     |
[INFO] [stdout] 868 |     pub trait Summary {
[INFO] [stdout]     |               ------- method in this trait
[INFO] [stdout] 869 |         fn summarize(&self) -> String; // 一行一个方法签名且都以分号结尾
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `content` is never read
[INFO] [stdout]    --> src/main.rs:877:13
[INFO] [stdout]     |
[INFO] [stdout] 873 |     pub struct NewsArticle {
[INFO] [stdout]     |                ----------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 877 |         pub content: String,
[INFO] [stdout]     |             ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `reply` and `retweet` are never read
[INFO] [stdout]    --> src/main.rs:887:13
[INFO] [stdout]     |
[INFO] [stdout] 884 |     pub struct Tweet {
[INFO] [stdout]     |                ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 887 |         pub reply: bool,
[INFO] [stdout]     |             ^^^^^
[INFO] [stdout] 888 |         pub retweet: bool,
[INFO] [stdout]     |             ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/main.rs:944:12
[INFO] [stdout]     |
[INFO] [stdout] 943 |     impl<T> Pair<T> {
[INFO] [stdout]     |     --------------- associated function in this implementation
[INFO] [stdout] 944 |         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/main.rs:949:12
[INFO] [stdout]     |
[INFO] [stdout] 948 |     impl<T: Display + PartialOrd> Pair<T> {
[INFO] [stdout]     |     ------------------------------------- method in this implementation
[INFO] [stdout] 949 |         fn cmp_display(&self) {
[INFO] [stdout]     |            ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lifetime_syntax` is never used
[INFO] [stdout]    --> src/main.rs:960:4
[INFO] [stdout]     |
[INFO] [stdout] 960 | fn lifetime_syntax() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `announce_and_return_part` is never used
[INFO] [stdout]     --> src/main.rs:1017:12
[INFO] [stdout]      |
[INFO] [stdout] 1016 |     impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]      |     ----------------------------- method in this implementation
[INFO] [stdout] 1017 |         fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]      |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `wirting_tests` is never used
[INFO] [stdout]     --> src/main.rs:1041:4
[INFO] [stdout]      |
[INFO] [stdout] 1041 | fn wirting_tests() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `running_tests` is never used
[INFO] [stdout]     --> src/main.rs:1056:4
[INFO] [stdout]      |
[INFO] [stdout] 1056 | fn running_tests() {}
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `closures` is never used
[INFO] [stdout]     --> src/main.rs:1059:4
[INFO] [stdout]      |
[INFO] [stdout] 1059 | fn closures() {
[INFO] [stdout]      |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `giveaway` and `most_stocked` are never used
[INFO] [stdout]     --> src/main.rs:1072:12
[INFO] [stdout]      |
[INFO] [stdout] 1071 |     impl Inventory {
[INFO] [stdout]      |     -------------- methods in this implementation
[INFO] [stdout] 1072 |         fn giveaway(&self, user_perference: Option<ShirtColor>) -> ShirtColor {
[INFO] [stdout]      |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1077 |         fn most_stocked(&self) -> ShirtColor {
[INFO] [stdout]      |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `iterators` is never used
[INFO] [stdout]     --> src/main.rs:1145:4
[INFO] [stdout]      |
[INFO] [stdout] 1145 | fn iterators() {
[INFO] [stdout]      |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `performance` is never used
[INFO] [stdout]     --> src/main.rs:1231:4
[INFO] [stdout]      |
[INFO] [stdout] 1231 | fn performance() {
[INFO] [stdout]      |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `release_profiles` is never used
[INFO] [stdout]     --> src/main.rs:1236:4
[INFO] [stdout]      |
[INFO] [stdout] 1236 | fn release_profiles() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `cargo_workspace` is never used
[INFO] [stdout]     --> src/main.rs:1241:4
[INFO] [stdout]      |
[INFO] [stdout] 1241 | fn cargo_workspace() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `re_box` is never used
[INFO] [stdout]     --> src/main.rs:1250:4
[INFO] [stdout]      |
[INFO] [stdout] 1250 | fn re_box() {
[INFO] [stdout]      |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `deref` is never used
[INFO] [stdout]     --> src/main.rs:1273:4
[INFO] [stdout]      |
[INFO] [stdout] 1273 | fn deref() {
[INFO] [stdout]      |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]     --> src/main.rs:1293:12
[INFO] [stdout]      |
[INFO] [stdout] 1292 |     impl<T> MyBox<T> {
[INFO] [stdout]      |     ---------------- associated function in this implementation
[INFO] [stdout] 1293 |         fn new(x: T) -> MyBox<T> {
[INFO] [stdout]      |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `re_drop` is never used
[INFO] [stdout]     --> src/main.rs:1312:4
[INFO] [stdout]      |
[INFO] [stdout] 1312 | fn re_drop() {
[INFO] [stdout]      |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `rc` is never used
[INFO] [stdout]     --> src/main.rs:1340:4
[INFO] [stdout]      |
[INFO] [stdout] 1340 | fn rc() {
[INFO] [stdout]      |    ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `interior_mutability` is never used
[INFO] [stdout]     --> src/main.rs:1358:4
[INFO] [stdout]      |
[INFO] [stdout] 1358 | fn interior_mutability() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `reference_cycles` is never used
[INFO] [stdout]     --> src/main.rs:1372:4
[INFO] [stdout]      |
[INFO] [stdout] 1372 | fn reference_cycles() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `tail` is never used
[INFO] [stdout]     --> src/main.rs:1383:12
[INFO] [stdout]      |
[INFO] [stdout] 1382 |     impl List {
[INFO] [stdout]      |     --------- method in this implementation
[INFO] [stdout] 1383 |         fn tail(&self) -> Option<&RefCell<Rc<List>>> {
[INFO] [stdout]      |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `threads` is never used
[INFO] [stdout]     --> src/main.rs:1481:4
[INFO] [stdout]      |
[INFO] [stdout] 1481 | fn threads() {
[INFO] [stdout]      |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `message_passing` is never used
[INFO] [stdout]     --> src/main.rs:1523:4
[INFO] [stdout]      |
[INFO] [stdout] 1523 | fn message_passing() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `shared_state` is never used
[INFO] [stdout]     --> src/main.rs:1600:4
[INFO] [stdout]      |
[INFO] [stdout] 1600 | fn shared_state() {
[INFO] [stdout]      |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `extensible_concurrency_sync_and_send` is never used
[INFO] [stdout]     --> src/main.rs:1633:4
[INFO] [stdout]      |
[INFO] [stdout] 1633 | fn extensible_concurrency_sync_and_send() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `what_is_oo` is never used
[INFO] [stdout]     --> src/main.rs:1647:4
[INFO] [stdout]      |
[INFO] [stdout] 1647 | fn what_is_oo() {
[INFO] [stdout]      |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `add`, `remove`, `average`, and `update_average` are never used
[INFO] [stdout]     --> src/main.rs:1659:16
[INFO] [stdout]      |
[INFO] [stdout] 1658 |     impl AverageCollection {
[INFO] [stdout]      |     ---------------------- methods in this implementation
[INFO] [stdout] 1659 |         pub fn add(&mut self, value: i32) {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] ...
[INFO] [stdout] 1663 |         pub fn remove(&mut self) -> Option<i32> {
[INFO] [stdout]      |                ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1673 |         pub fn average(&self) -> f64 {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1676 |         fn update_average(&mut self) {
[INFO] [stdout]      |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `trait_objects` is never used
[INFO] [stdout]     --> src/main.rs:1694:4
[INFO] [stdout]      |
[INFO] [stdout] 1694 | fn trait_objects() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `draw` is never used
[INFO] [stdout]     --> src/main.rs:1697:12
[INFO] [stdout]      |
[INFO] [stdout] 1696 |     pub trait Draw {
[INFO] [stdout]      |               ---- method in this trait
[INFO] [stdout] 1697 |         fn draw(&self) {}
[INFO] [stdout]      |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `run` is never used
[INFO] [stdout]     --> src/main.rs:1704:16
[INFO] [stdout]      |
[INFO] [stdout] 1703 |     impl Screen {
[INFO] [stdout]      |     ----------- method in this implementation
[INFO] [stdout] 1704 |         pub fn run(&self) {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width`, `height`, and `label` are never read
[INFO] [stdout]     --> src/main.rs:1712:13
[INFO] [stdout]      |
[INFO] [stdout] 1711 |     pub struct Button {
[INFO] [stdout]      |                ------ fields in this struct
[INFO] [stdout] 1712 |         pub width: u32,
[INFO] [stdout]      |             ^^^^^
[INFO] [stdout] 1713 |         pub height: u32,
[INFO] [stdout]      |             ^^^^^^
[INFO] [stdout] 1714 |         pub label: String,
[INFO] [stdout]      |             ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width`, `height`, and `options` are never read
[INFO] [stdout]     --> src/main.rs:1722:9
[INFO] [stdout]      |
[INFO] [stdout] 1721 |     pub struct SelectBox {
[INFO] [stdout]      |                --------- fields in this struct
[INFO] [stdout] 1722 |         width: u32,
[INFO] [stdout]      |         ^^^^^
[INFO] [stdout] 1723 |         height: u32,
[INFO] [stdout]      |         ^^^^^^
[INFO] [stdout] 1724 |         options: Vec<String>,
[INFO] [stdout]      |         ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `oo_design_patterns` is never used
[INFO] [stdout]     --> src/main.rs:1751:4
[INFO] [stdout]      |
[INFO] [stdout] 1751 | fn oo_design_patterns() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `add_text`, `content`, `request_review`, and `approve` are never used
[INFO] [stdout]     --> src/main.rs:1759:16
[INFO] [stdout]      |
[INFO] [stdout] 1758 |     impl Post {
[INFO] [stdout]      |     --------- associated items in this implementation
[INFO] [stdout] 1759 |         pub fn new() -> Post {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] ...
[INFO] [stdout] 1765 |         pub fn add_text(&mut self, text: &str) {
[INFO] [stdout]      |                ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1768 |         pub fn content(&self) -> &str {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1771 |         pub fn request_review(&mut self) {
[INFO] [stdout]      |                ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1776 |         pub fn approve(&mut self) {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `all_the_places_for_patterns` is never used
[INFO] [stdout]     --> src/main.rs:1830:4
[INFO] [stdout]      |
[INFO] [stdout] 1830 | fn all_the_places_for_patterns() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `refutability` is never used
[INFO] [stdout]     --> src/main.rs:1885:4
[INFO] [stdout]      |
[INFO] [stdout] 1885 | fn refutability() {
[INFO] [stdout]      |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `pattern_syntax` is never used
[INFO] [stdout]     --> src/main.rs:1894:4
[INFO] [stdout]      |
[INFO] [stdout] 1894 | fn pattern_syntax() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `unsafe_rust` is never used
[INFO] [stdout]     --> src/main.rs:2065:4
[INFO] [stdout]      |
[INFO] [stdout] 2065 | fn unsafe_rust() {
[INFO] [stdout]      |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `advanced_traits` is never used
[INFO] [stdout]     --> src/main.rs:2156:4
[INFO] [stdout]      |
[INFO] [stdout] 2156 | fn advanced_traits() {}
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `advanced_types` is never used
[INFO] [stdout]     --> src/main.rs:2159:4
[INFO] [stdout]      |
[INFO] [stdout] 2159 | fn advanced_types() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `returns_closure` is never used
[INFO] [stdout]     --> src/main.rs:2191:8
[INFO] [stdout]      |
[INFO] [stdout] 2191 |     fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
[INFO] [stdout]      |        ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `macros` is never used
[INFO] [stdout]     --> src/main.rs:2197:4
[INFO] [stdout]      |
[INFO] [stdout] 2197 | fn macros() {
[INFO] [stdout]      |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `abs` is never used
[INFO] [stdout]     --> src/main.rs:2132:12
[INFO] [stdout]      |
[INFO] [stdout] 2132 |         fn abs(input: i32) -> i32;
[INFO] [stdout]      |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `Alaska` should have a snake case name
[INFO] [stdout]    --> src/main.rs:533:9
[INFO] [stdout]     |
[INFO] [stdout] 533 |     let Alaska = Coin::Quarter(UsState::Alaska);
[INFO] [stdout]     |         ^^^^^^ help: convert the identifier to snake case: `alaska`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: creating a shared reference to mutable static is discouraged
[INFO] [stdout]     --> src/main.rs:2148:38
[INFO] [stdout]      |
[INFO] [stdout] 2148 |     unsafe { println!("COUNTER: {}", COUNTER) }
[INFO] [stdout]      |                                      ^^^^^^^ shared reference to mutable static
[INFO] [stdout]      |
[INFO] [stdout]      = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
[INFO] [stdout]      = note: shared references to mutable statics are dangerous; it's undefined behavior if the static is mutated or if a mutable reference is created for it while the shared reference lives
[INFO] [stdout]      = note: `#[warn(static_mut_refs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.13s
[INFO] running `Command { std: "docker" "inspect" "31c641287c4e20c318e34957ee3160f8a526b354d4f5d4dfcb7fc29eaf8e14e4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31c641287c4e20c318e34957ee3160f8a526b354d4f5d4dfcb7fc29eaf8e14e4", kill_on_drop: false }`
[INFO] [stdout] 31c641287c4e20c318e34957ee3160f8a526b354d4f5d4dfcb7fc29eaf8e14e4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e6fa135eeb1fe0eb4a17072ada062f4d58b3f41473cce5f96a484ce8313c0ba4
[INFO] running `Command { std: "docker" "start" "-a" "e6fa135eeb1fe0eb4a17072ada062f4d58b3f41473cce5f96a484ce8313c0ba4", kill_on_drop: false }`
[INFO] [stderr]    Compiling learning-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `order1`
[INFO] [stdout]   --> src/lib.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let order1 = back_of_house::Appetizer::Soup;
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_order1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `deliver_order` is never used
[INFO] [stdout]   --> src/lib.rs:16:4
[INFO] [stdout]    |
[INFO] [stdout] 16 | fn deliver_order() {}
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `eat_at_restaurant` is never used
[INFO] [stdout]   --> src/lib.rs:43:4
[INFO] [stdout]    |
[INFO] [stdout] 43 | fn eat_at_restaurant() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/lib.rs:56:8
[INFO] [stdout]    |
[INFO] [stdout] 56 | struct Rectangle {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `can_hold` is never used
[INFO] [stdout]   --> src/lib.rs:62:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | impl Rectangle {
[INFO] [stdout]    | -------------- method in this implementation
[INFO] [stdout] 62 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `add_to_waitlist` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn add_to_waitlist() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `seat_at_table` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn seat_at_table() {}
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 |     fn take_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `serve_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn serve_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_payment` is never used
[INFO] [stdout]  --> src/front_of_house.rs:6:8
[INFO] [stdout]   |
[INFO] [stdout] 6 |     fn take_payment() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Appetizer` is never used
[INFO] [stdout]   --> src/lib.rs:19:14
[INFO] [stdout]    |
[INFO] [stdout] 19 |     pub enum Appetizer {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `fix_incorrect_order` is never used
[INFO] [stdout]   --> src/lib.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn fix_incorrect_order() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `cook_order` is never used
[INFO] [stdout]   --> src/lib.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn cook_order() {}
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Breakfast` is never constructed
[INFO] [stdout]   --> src/lib.rs:29:16
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub struct Breakfast {
[INFO] [stdout]    |                ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `summer` is never used
[INFO] [stdout]   --> src/lib.rs:34:16
[INFO] [stdout]    |
[INFO] [stdout] 33 |     impl Breakfast {
[INFO] [stdout]    |     -------------- associated function in this implementation
[INFO] [stdout] 34 |         pub fn summer(toast: &str) -> Breakfast {
[INFO] [stdout]    |                ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `order1`
[INFO] [stdout]   --> src/lib.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let order1 = back_of_house::Appetizer::Soup;
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_order1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::num`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use core::num;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `hash::Hash`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     hash::Hash,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `deliver_order` is never used
[INFO] [stdout]   --> src/lib.rs:16:4
[INFO] [stdout]    |
[INFO] [stdout] 16 | fn deliver_order() {}
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `eat_at_restaurant` is never used
[INFO] [stdout]   --> src/lib.rs:43:4
[INFO] [stdout]    |
[INFO] [stdout] 43 | fn eat_at_restaurant() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `add_to_waitlist` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn add_to_waitlist() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `seat_at_table` is never used
[INFO] [stdout]  --> src/front_of_house/hosting.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn seat_at_table() {}
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 |     fn take_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `serve_order` is never used
[INFO] [stdout]  --> src/front_of_house.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn serve_order() {}
[INFO] [stdout]   |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `take_payment` is never used
[INFO] [stdout]  --> src/front_of_house.rs:6:8
[INFO] [stdout]   |
[INFO] [stdout] 6 |     fn take_payment() {}
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Appetizer` is never used
[INFO] [stdout]   --> src/lib.rs:19:14
[INFO] [stdout]    |
[INFO] [stdout] 19 |     pub enum Appetizer {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `fix_incorrect_order` is never used
[INFO] [stdout]   --> src/lib.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn fix_incorrect_order() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `cook_order` is never used
[INFO] [stdout]   --> src/lib.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn cook_order() {}
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Breakfast` is never constructed
[INFO] [stdout]   --> src/lib.rs:29:16
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub struct Breakfast {
[INFO] [stdout]    |                ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `summer` is never used
[INFO] [stdout]   --> src/lib.rs:34:16
[INFO] [stdout]    |
[INFO] [stdout] 33 |     impl Breakfast {
[INFO] [stdout]    |     -------------- associated function in this implementation
[INFO] [stdout] 34 |         pub fn summer(toast: &str) -> Breakfast {
[INFO] [stdout]    |                ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: cannot test inner items
[INFO] [stdout]     --> src/main.rs:1159:5
[INFO] [stdout]      |
[INFO] [stdout] 1159 |     #[test]
[INFO] [stdout]      |     ^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(unnameable_test_items)]` on by default
[INFO] [stdout]      = note: this warning originates in the attribute macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: cannot test inner items
[INFO] [stdout]     --> src/main.rs:1170:5
[INFO] [stdout]      |
[INFO] [stdout] 1170 |     #[test]
[INFO] [stdout]      |     ^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: this warning originates in the attribute macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Read`
[INFO] [stdout]   --> src/main.rs:12:27
[INFO] [stdout]    |
[INFO] [stdout] 12 |     io::{self, ErrorKind, Read},
[INFO] [stdout]    |                           ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `borrow::Borrow`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     borrow::Borrow,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]    --> src/main.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |     let c = 'z';
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]    --> src/main.rs:134:9
[INFO] [stdout]     |
[INFO] [stdout] 134 |     let z: char = '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/main.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     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/main.rs:144:9
[INFO] [stdout]     |
[INFO] [stdout] 144 |     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/main.rs:145:9
[INFO] [stdout]     |
[INFO] [stdout] 145 |     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/main.rs:146:9
[INFO] [stdout]     |
[INFO] [stdout] 146 |     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: `months`
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 |     let months: [&str; 12] = [
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `first`
[INFO] [stdout]    --> src/main.rs:163:9
[INFO] [stdout]     |
[INFO] [stdout] 163 |     let first = a[0]; // 使用索引访问
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_first`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:173:9
[INFO] [stdout]     |
[INFO] [stdout] 173 |     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: `number`
[INFO] [stdout]    --> src/main.rs:206:9
[INFO] [stdout]     |
[INFO] [stdout] 206 |     let number = if condition { 5 } else { 6 }; // 分支返回的类型必须相同
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:281:9
[INFO] [stdout]     |
[INFO] [stdout] 281 |     let s2 = s1;
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]    --> src/main.rs:330:9
[INFO] [stdout]     |
[INFO] [stdout] 330 |     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: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:344:9
[INFO] [stdout]     |
[INFO] [stdout] 344 |     let mut s = String::from("hello world");
[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: unused variable: `user3`
[INFO] [stdout]    --> src/main.rs:382:9
[INFO] [stdout]     |
[INFO] [stdout] 382 |     let user3: User = 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/main.rs:390:9
[INFO] [stdout]     |
[INFO] [stdout] 390 |     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: `subject`
[INFO] [stdout]    --> src/main.rs:394:9
[INFO] [stdout]     |
[INFO] [stdout] 394 |     let subject = AlwaysEqual;
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_subject`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]    --> src/main.rs:463:9
[INFO] [stdout]     |
[INFO] [stdout] 463 |     let four = IpAddrkind::V4(String::from("127.0.0.1"));
[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/main.rs:464:9
[INFO] [stdout]     |
[INFO] [stdout] 464 |     let six = IpAddrkind::V6(String::from("::1"));
[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/main.rs:469:9
[INFO] [stdout]     |
[INFO] [stdout] 469 |     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] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]    --> src/main.rs:470:9
[INFO] [stdout]     |
[INFO] [stdout] 470 |     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: `some_number`
[INFO] [stdout]    --> src/main.rs:498:9
[INFO] [stdout]     |
[INFO] [stdout] 498 |     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_char`
[INFO] [stdout]    --> src/main.rs:499:9
[INFO] [stdout]     |
[INFO] [stdout] 499 |     let some_char = Some('e');
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]    --> src/main.rs:500:9
[INFO] [stdout]     |
[INFO] [stdout] 500 |     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: `six`
[INFO] [stdout]    --> src/main.rs:545:9
[INFO] [stdout]     |
[INFO] [stdout] 545 |     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: `none`
[INFO] [stdout]    --> src/main.rs:546:9
[INFO] [stdout]     |
[INFO] [stdout] 546 |     let none = plus_one(None);
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]    --> src/main.rs:612:9
[INFO] [stdout]     |
[INFO] [stdout] 612 |     let v: Vec<i32> = Vec::new();
[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/main.rs:619:9
[INFO] [stdout]     |
[INFO] [stdout] 619 |     let third = &v[2];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_third`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]    --> src/main.rs:637:9
[INFO] [stdout]     |
[INFO] [stdout] 637 |     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/main.rs:648:9
[INFO] [stdout]     |
[INFO] [stdout] 648 |     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/main.rs:649:9
[INFO] [stdout]     |
[INFO] [stdout] 649 |     let s = "initial contents".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/main.rs:661:9
[INFO] [stdout]     |
[INFO] [stdout] 661 |     let s = format!("{s1}-{s2}");
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:664:9
[INFO] [stdout]     |
[INFO] [stdout] 664 |     let s1 = String::from("hello");
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/main.rs:669:9
[INFO] [stdout]     |
[INFO] [stdout] 669 |     let s = &hello[0..4]; // Зд 每个字母长度为 2 字节
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file_result`
[INFO] [stdout]    --> src/main.rs:735:9
[INFO] [stdout]     |
[INFO] [stdout] 735 |     let greeting_file_result = File::open("hello.txt");
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:750:9
[INFO] [stdout]     |
[INFO] [stdout] 750 |     let greeting_file = File::open("hello.txt").unwrap_or_else(|error| {
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:762:9
[INFO] [stdout]     |
[INFO] [stdout] 762 |     let greeting_file = File::open("hello.txt").unwrap();
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]    --> src/main.rs:764:9
[INFO] [stdout]     |
[INFO] [stdout] 764 |     let greeting_file =
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `integer`
[INFO] [stdout]    --> src/main.rs:834:9
[INFO] [stdout]     |
[INFO] [stdout] 834 |     let integer = Point { x: 5, y: 10 };
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `float`
[INFO] [stdout]    --> src/main.rs:835:9
[INFO] [stdout]     |
[INFO] [stdout] 835 |     let float = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:815:13
[INFO] [stdout]     |
[INFO] [stdout] 815 |         for item in list {
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:814:13
[INFO] [stdout]     |
[INFO] [stdout] 814 |         let mut largest = &list[0];
[INFO] [stdout]     |             ----^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:920:41
[INFO] [stdout]     |
[INFO] [stdout] 920 |     pub fn notify<T: Summary + Display>(item: &T) {}
[INFO] [stdout]     |                                         ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:923:28
[INFO] [stdout]     |
[INFO] [stdout] 923 |     fn some_function<T, U>(t: &T, u: &U)
[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/main.rs:923:35
[INFO] [stdout]     |
[INFO] [stdout] 923 |     fn some_function<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                                   ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]     --> src/main.rs:1002:9
[INFO] [stdout]      |
[INFO] [stdout] 1002 |     let i = ImportantExcerpt {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]     --> src/main.rs:1024:9
[INFO] [stdout]      |
[INFO] [stdout] 1024 |     let s: &'static str = "I have a static lifetime";
[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/main.rs:989:32
[INFO] [stdout]     |
[INFO] [stdout] 989 |     fn longest<'a>(x: &'a str, y: &str) -> &'a str {
[INFO] [stdout]     |                                ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]     --> src/main.rs:1112:9
[INFO] [stdout]      |
[INFO] [stdout] 1112 |     let s = example_closure("Hello".to_string());
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list`
[INFO] [stdout]     --> src/main.rs:1268:9
[INFO] [stdout]      |
[INFO] [stdout] 1268 |     let list = Cons(1, Box::new(Cons(2, Box::new(Cons(3, Box::new(Nil))))));
[INFO] [stdout]      |         ^^^^ help: if this is intentional, prefix it with an underscore: `_list`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]     --> src/main.rs:1321:9
[INFO] [stdout]      |
[INFO] [stdout] 1321 |     let c = CustomSmartPointer {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `d`
[INFO] [stdout]     --> src/main.rs:1324:9
[INFO] [stdout]      |
[INFO] [stdout] 1324 |     let d = CustomSmartPointer {
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_d`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]     --> src/main.rs:1349:9
[INFO] [stdout]      |
[INFO] [stdout] 1349 |     let b = Cons(3, Rc::clone(&a)); // 不会拷贝, 只会操作引用计数从 1 -> 2
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]     --> src/main.rs:1352:13
[INFO] [stdout]      |
[INFO] [stdout] 1352 |         let c = Cons(4, Rc::clone(&a)); // 不会拷贝, 只会操作引用计数从 2 -> 3
[INFO] [stdout]      |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `post`
[INFO] [stdout]     --> src/main.rs:1785:31
[INFO] [stdout]      |
[INFO] [stdout] 1785 |         fn content<'a>(&self, post: &'a Post) -> &'a str {
[INFO] [stdout]      |                               ^^^^ help: if this is intentional, prefix it with an underscore: `_post`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1871:9
[INFO] [stdout]      |
[INFO] [stdout] 1871 |     let x = 5;
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1873:10
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[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/main.rs:1873:13
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[INFO] [stdout]      |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]     --> src/main.rs:1873:16
[INFO] [stdout]      |
[INFO] [stdout] 1873 |     let (x, y, z) = (1, 2, 3);
[INFO] [stdout]      |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]     --> src/main.rs:1876:12
[INFO] [stdout]      |
[INFO] [stdout] 1876 |     fn foo(x: i32) {}
[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/main.rs:2021:9
[INFO] [stdout]      |
[INFO] [stdout] 2021 |     let y = 10;
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]     --> src/main.rs:2167:9
[INFO] [stdout]      |
[INFO] [stdout] 2167 |     let f: Thunk = Box::new(|| println!("hi"));
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]     --> src/main.rs:2168:24
[INFO] [stdout]      |
[INFO] [stdout] 2168 |     fn takes_long_type(f: Thunk) {}
[INFO] [stdout]      |                        ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]     --> src/main.rs:2211:9
[INFO] [stdout]      |
[INFO] [stdout] 2211 |     let v: Vec<i32> = vec![1, 2, 3];
[INFO] [stdout]      |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `guess_number` is never used
[INFO] [stdout]   --> src/main.rs:64:4
[INFO] [stdout]    |
[INFO] [stdout] 64 | fn guess_number() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `variables_and_mutability` is never used
[INFO] [stdout]   --> src/main.rs:95:4
[INFO] [stdout]    |
[INFO] [stdout] 95 | fn variables_and_mutability() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `data_types` is never used
[INFO] [stdout]    --> src/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn data_types() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `another_function` is never used
[INFO] [stdout]    --> src/main.rs:166:4
[INFO] [stdout]     |
[INFO] [stdout] 166 | fn another_function(x: i32) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `control_flow` is never used
[INFO] [stdout]    --> src/main.rs:192:4
[INFO] [stdout]     |
[INFO] [stdout] 192 | fn control_flow() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `ownership` is never used
[INFO] [stdout]    --> src/main.rs:272:4
[INFO] [stdout]     |
[INFO] [stdout] 272 | fn ownership() {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `references_and_borrowing` is never used
[INFO] [stdout]    --> src/main.rs:312:4
[INFO] [stdout]     |
[INFO] [stdout] 312 | fn references_and_borrowing() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `slices` is never used
[INFO] [stdout]    --> src/main.rs:343:4
[INFO] [stdout]     |
[INFO] [stdout] 343 | fn slices() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_structs` is never used
[INFO] [stdout]    --> src/main.rs:359:4
[INFO] [stdout]     |
[INFO] [stdout] 359 | fn defining_structs() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `example_structs` is never used
[INFO] [stdout]    --> src/main.rs:397:4
[INFO] [stdout]     |
[INFO] [stdout] 397 | fn example_structs() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `method_syntax` is never used
[INFO] [stdout]    --> src/main.rs:417:4
[INFO] [stdout]     |
[INFO] [stdout] 417 | fn method_syntax() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `area` is never used
[INFO] [stdout]    --> src/main.rs:424:12
[INFO] [stdout]     |
[INFO] [stdout] 423 |     impl Rectangle {
[INFO] [stdout]     |     -------------- method in this implementation
[INFO] [stdout] 424 |         fn area(self: &Self) -> u32 {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `can_hold` and `square` are never used
[INFO] [stdout]    --> src/main.rs:429:12
[INFO] [stdout]     |
[INFO] [stdout] 428 |     impl Rectangle {
[INFO] [stdout]     |     -------------- associated items in this implementation
[INFO] [stdout] 429 |         fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 432 |         fn square(size: u32) -> Self {
[INFO] [stdout]     |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_an_enum` is never used
[INFO] [stdout]    --> src/main.rs:458:4
[INFO] [stdout]     |
[INFO] [stdout] 458 | fn defining_an_enum() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `call` is never used
[INFO] [stdout]    --> src/main.rs:490:12
[INFO] [stdout]     |
[INFO] [stdout] 489 |     impl Message {
[INFO] [stdout]     |     ------------ method in this implementation
[INFO] [stdout] 490 |         fn call(&self) {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `match_flow` is never used
[INFO] [stdout]    --> src/main.rs:505:4
[INFO] [stdout]     |
[INFO] [stdout] 505 | fn match_flow() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `if_let` is never used
[INFO] [stdout]    --> src/main.rs:564:4
[INFO] [stdout]     |
[INFO] [stdout] 564 | fn if_let() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `defining_modules_to_control_scope_and_privacy` is never used
[INFO] [stdout]    --> src/main.rs:594:4
[INFO] [stdout]     |
[INFO] [stdout] 594 | fn defining_modules_to_control_scope_and_privacy() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `paths_for_referring_to_an_item_in_the_module_tree` is never used
[INFO] [stdout]    --> src/main.rs:599:4
[INFO] [stdout]     |
[INFO] [stdout] 599 | fn paths_for_referring_to_an_item_in_the_module_tree() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `vectors` is never used
[INFO] [stdout]    --> src/main.rs:611:4
[INFO] [stdout]     |
[INFO] [stdout] 611 | fn vectors() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strings` is never used
[INFO] [stdout]    --> src/main.rs:645:4
[INFO] [stdout]     |
[INFO] [stdout] 645 | fn strings() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `hash_maps` is never used
[INFO] [stdout]    --> src/main.rs:687:4
[INFO] [stdout]     |
[INFO] [stdout] 687 | fn hash_maps() {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `unrecoverable_errors_with_panic` is never used
[INFO] [stdout]    --> src/main.rs:728:4
[INFO] [stdout]     |
[INFO] [stdout] 728 | fn unrecoverable_errors_with_panic() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `recoverable_errors_with_result` is never used
[INFO] [stdout]    --> src/main.rs:734:4
[INFO] [stdout]     |
[INFO] [stdout] 734 | fn recoverable_errors_with_result() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `to_panic_or_not_to_panic` is never used
[INFO] [stdout]    --> src/main.rs:803:4
[INFO] [stdout]     |
[INFO] [stdout] 803 | fn to_panic_or_not_to_panic() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `syntax` is never used
[INFO] [stdout]    --> src/main.rs:811:4
[INFO] [stdout]     |
[INFO] [stdout] 811 | fn syntax() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `x` is never used
[INFO] [stdout]    --> src/main.rs:848:12
[INFO] [stdout]     |
[INFO] [stdout] 847 |     impl<T> Point<T> {
[INFO] [stdout]     |     ---------------- method in this implementation
[INFO] [stdout] 848 |         fn x(&self) -> &T {
[INFO] [stdout]     |            ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `distance_from_origin` is never used
[INFO] [stdout]    --> src/main.rs:857:12
[INFO] [stdout]     |
[INFO] [stdout] 856 |     impl Point<f32> {
[INFO] [stdout]     |     --------------- method in this implementation
[INFO] [stdout] 857 |         fn distance_from_origin(&self) -> f32 {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `traits` is never used
[INFO] [stdout]    --> src/main.rs:865:4
[INFO] [stdout]     |
[INFO] [stdout] 865 | fn traits() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `summarize` is never used
[INFO] [stdout]    --> src/main.rs:869:12
[INFO] [stdout]     |
[INFO] [stdout] 868 |     pub trait Summary {
[INFO] [stdout]     |               ------- method in this trait
[INFO] [stdout] 869 |         fn summarize(&self) -> String; // 一行一个方法签名且都以分号结尾
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `content` is never read
[INFO] [stdout]    --> src/main.rs:877:13
[INFO] [stdout]     |
[INFO] [stdout] 873 |     pub struct NewsArticle {
[INFO] [stdout]     |                ----------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 877 |         pub content: String,
[INFO] [stdout]     |             ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `reply` and `retweet` are never read
[INFO] [stdout]    --> src/main.rs:887:13
[INFO] [stdout]     |
[INFO] [stdout] 884 |     pub struct Tweet {
[INFO] [stdout]     |                ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 887 |         pub reply: bool,
[INFO] [stdout]     |             ^^^^^
[INFO] [stdout] 888 |         pub retweet: bool,
[INFO] [stdout]     |             ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]    --> src/main.rs:944:12
[INFO] [stdout]     |
[INFO] [stdout] 943 |     impl<T> Pair<T> {
[INFO] [stdout]     |     --------------- associated function in this implementation
[INFO] [stdout] 944 |         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/main.rs:949:12
[INFO] [stdout]     |
[INFO] [stdout] 948 |     impl<T: Display + PartialOrd> Pair<T> {
[INFO] [stdout]     |     ------------------------------------- method in this implementation
[INFO] [stdout] 949 |         fn cmp_display(&self) {
[INFO] [stdout]     |            ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lifetime_syntax` is never used
[INFO] [stdout]    --> src/main.rs:960:4
[INFO] [stdout]     |
[INFO] [stdout] 960 | fn lifetime_syntax() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `announce_and_return_part` is never used
[INFO] [stdout]     --> src/main.rs:1017:12
[INFO] [stdout]      |
[INFO] [stdout] 1016 |     impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]      |     ----------------------------- method in this implementation
[INFO] [stdout] 1017 |         fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]      |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `wirting_tests` is never used
[INFO] [stdout]     --> src/main.rs:1041:4
[INFO] [stdout]      |
[INFO] [stdout] 1041 | fn wirting_tests() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `running_tests` is never used
[INFO] [stdout]     --> src/main.rs:1056:4
[INFO] [stdout]      |
[INFO] [stdout] 1056 | fn running_tests() {}
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `closures` is never used
[INFO] [stdout]     --> src/main.rs:1059:4
[INFO] [stdout]      |
[INFO] [stdout] 1059 | fn closures() {
[INFO] [stdout]      |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `giveaway` and `most_stocked` are never used
[INFO] [stdout]     --> src/main.rs:1072:12
[INFO] [stdout]      |
[INFO] [stdout] 1071 |     impl Inventory {
[INFO] [stdout]      |     -------------- methods in this implementation
[INFO] [stdout] 1072 |         fn giveaway(&self, user_perference: Option<ShirtColor>) -> ShirtColor {
[INFO] [stdout]      |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1077 |         fn most_stocked(&self) -> ShirtColor {
[INFO] [stdout]      |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `iterators` is never used
[INFO] [stdout]     --> src/main.rs:1145:4
[INFO] [stdout]      |
[INFO] [stdout] 1145 | fn iterators() {
[INFO] [stdout]      |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `performance` is never used
[INFO] [stdout]     --> src/main.rs:1231:4
[INFO] [stdout]      |
[INFO] [stdout] 1231 | fn performance() {
[INFO] [stdout]      |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `release_profiles` is never used
[INFO] [stdout]     --> src/main.rs:1236:4
[INFO] [stdout]      |
[INFO] [stdout] 1236 | fn release_profiles() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `cargo_workspace` is never used
[INFO] [stdout]     --> src/main.rs:1241:4
[INFO] [stdout]      |
[INFO] [stdout] 1241 | fn cargo_workspace() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `re_box` is never used
[INFO] [stdout]     --> src/main.rs:1250:4
[INFO] [stdout]      |
[INFO] [stdout] 1250 | fn re_box() {
[INFO] [stdout]      |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `deref` is never used
[INFO] [stdout]     --> src/main.rs:1273:4
[INFO] [stdout]      |
[INFO] [stdout] 1273 | fn deref() {
[INFO] [stdout]      |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]     --> src/main.rs:1293:12
[INFO] [stdout]      |
[INFO] [stdout] 1292 |     impl<T> MyBox<T> {
[INFO] [stdout]      |     ---------------- associated function in this implementation
[INFO] [stdout] 1293 |         fn new(x: T) -> MyBox<T> {
[INFO] [stdout]      |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `re_drop` is never used
[INFO] [stdout]     --> src/main.rs:1312:4
[INFO] [stdout]      |
[INFO] [stdout] 1312 | fn re_drop() {
[INFO] [stdout]      |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `rc` is never used
[INFO] [stdout]     --> src/main.rs:1340:4
[INFO] [stdout]      |
[INFO] [stdout] 1340 | fn rc() {
[INFO] [stdout]      |    ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `interior_mutability` is never used
[INFO] [stdout]     --> src/main.rs:1358:4
[INFO] [stdout]      |
[INFO] [stdout] 1358 | fn interior_mutability() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `reference_cycles` is never used
[INFO] [stdout]     --> src/main.rs:1372:4
[INFO] [stdout]      |
[INFO] [stdout] 1372 | fn reference_cycles() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `tail` is never used
[INFO] [stdout]     --> src/main.rs:1383:12
[INFO] [stdout]      |
[INFO] [stdout] 1382 |     impl List {
[INFO] [stdout]      |     --------- method in this implementation
[INFO] [stdout] 1383 |         fn tail(&self) -> Option<&RefCell<Rc<List>>> {
[INFO] [stdout]      |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `threads` is never used
[INFO] [stdout]     --> src/main.rs:1481:4
[INFO] [stdout]      |
[INFO] [stdout] 1481 | fn threads() {
[INFO] [stdout]      |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `message_passing` is never used
[INFO] [stdout]     --> src/main.rs:1523:4
[INFO] [stdout]      |
[INFO] [stdout] 1523 | fn message_passing() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `shared_state` is never used
[INFO] [stdout]     --> src/main.rs:1600:4
[INFO] [stdout]      |
[INFO] [stdout] 1600 | fn shared_state() {
[INFO] [stdout]      |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `extensible_concurrency_sync_and_send` is never used
[INFO] [stdout]     --> src/main.rs:1633:4
[INFO] [stdout]      |
[INFO] [stdout] 1633 | fn extensible_concurrency_sync_and_send() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `what_is_oo` is never used
[INFO] [stdout]     --> src/main.rs:1647:4
[INFO] [stdout]      |
[INFO] [stdout] 1647 | fn what_is_oo() {
[INFO] [stdout]      |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `add`, `remove`, `average`, and `update_average` are never used
[INFO] [stdout]     --> src/main.rs:1659:16
[INFO] [stdout]      |
[INFO] [stdout] 1658 |     impl AverageCollection {
[INFO] [stdout]      |     ---------------------- methods in this implementation
[INFO] [stdout] 1659 |         pub fn add(&mut self, value: i32) {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] ...
[INFO] [stdout] 1663 |         pub fn remove(&mut self) -> Option<i32> {
[INFO] [stdout]      |                ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1673 |         pub fn average(&self) -> f64 {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1676 |         fn update_average(&mut self) {
[INFO] [stdout]      |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `trait_objects` is never used
[INFO] [stdout]     --> src/main.rs:1694:4
[INFO] [stdout]      |
[INFO] [stdout] 1694 | fn trait_objects() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `draw` is never used
[INFO] [stdout]     --> src/main.rs:1697:12
[INFO] [stdout]      |
[INFO] [stdout] 1696 |     pub trait Draw {
[INFO] [stdout]      |               ---- method in this trait
[INFO] [stdout] 1697 |         fn draw(&self) {}
[INFO] [stdout]      |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `run` is never used
[INFO] [stdout]     --> src/main.rs:1704:16
[INFO] [stdout]      |
[INFO] [stdout] 1703 |     impl Screen {
[INFO] [stdout]      |     ----------- method in this implementation
[INFO] [stdout] 1704 |         pub fn run(&self) {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width`, `height`, and `label` are never read
[INFO] [stdout]     --> src/main.rs:1712:13
[INFO] [stdout]      |
[INFO] [stdout] 1711 |     pub struct Button {
[INFO] [stdout]      |                ------ fields in this struct
[INFO] [stdout] 1712 |         pub width: u32,
[INFO] [stdout]      |             ^^^^^
[INFO] [stdout] 1713 |         pub height: u32,
[INFO] [stdout]      |             ^^^^^^
[INFO] [stdout] 1714 |         pub label: String,
[INFO] [stdout]      |             ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width`, `height`, and `options` are never read
[INFO] [stdout]     --> src/main.rs:1722:9
[INFO] [stdout]      |
[INFO] [stdout] 1721 |     pub struct SelectBox {
[INFO] [stdout]      |                --------- fields in this struct
[INFO] [stdout] 1722 |         width: u32,
[INFO] [stdout]      |         ^^^^^
[INFO] [stdout] 1723 |         height: u32,
[INFO] [stdout]      |         ^^^^^^
[INFO] [stdout] 1724 |         options: Vec<String>,
[INFO] [stdout]      |         ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `oo_design_patterns` is never used
[INFO] [stdout]     --> src/main.rs:1751:4
[INFO] [stdout]      |
[INFO] [stdout] 1751 | fn oo_design_patterns() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `add_text`, `content`, `request_review`, and `approve` are never used
[INFO] [stdout]     --> src/main.rs:1759:16
[INFO] [stdout]      |
[INFO] [stdout] 1758 |     impl Post {
[INFO] [stdout]      |     --------- associated items in this implementation
[INFO] [stdout] 1759 |         pub fn new() -> Post {
[INFO] [stdout]      |                ^^^
[INFO] [stdout] ...
[INFO] [stdout] 1765 |         pub fn add_text(&mut self, text: &str) {
[INFO] [stdout]      |                ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1768 |         pub fn content(&self) -> &str {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1771 |         pub fn request_review(&mut self) {
[INFO] [stdout]      |                ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 1776 |         pub fn approve(&mut self) {
[INFO] [stdout]      |                ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `all_the_places_for_patterns` is never used
[INFO] [stdout]     --> src/main.rs:1830:4
[INFO] [stdout]      |
[INFO] [stdout] 1830 | fn all_the_places_for_patterns() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `refutability` is never used
[INFO] [stdout]     --> src/main.rs:1885:4
[INFO] [stdout]      |
[INFO] [stdout] 1885 | fn refutability() {
[INFO] [stdout]      |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `pattern_syntax` is never used
[INFO] [stdout]     --> src/main.rs:1894:4
[INFO] [stdout]      |
[INFO] [stdout] 1894 | fn pattern_syntax() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `unsafe_rust` is never used
[INFO] [stdout]     --> src/main.rs:2065:4
[INFO] [stdout]      |
[INFO] [stdout] 2065 | fn unsafe_rust() {
[INFO] [stdout]      |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `advanced_traits` is never used
[INFO] [stdout]     --> src/main.rs:2156:4
[INFO] [stdout]      |
[INFO] [stdout] 2156 | fn advanced_traits() {}
[INFO] [stdout]      |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `advanced_types` is never used
[INFO] [stdout]     --> src/main.rs:2159:4
[INFO] [stdout]      |
[INFO] [stdout] 2159 | fn advanced_types() {
[INFO] [stdout]      |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `returns_closure` is never used
[INFO] [stdout]     --> src/main.rs:2191:8
[INFO] [stdout]      |
[INFO] [stdout] 2191 |     fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
[INFO] [stdout]      |        ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `macros` is never used
[INFO] [stdout]     --> src/main.rs:2197:4
[INFO] [stdout]      |
[INFO] [stdout] 2197 | fn macros() {
[INFO] [stdout]      |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `abs` is never used
[INFO] [stdout]     --> src/main.rs:2132:12
[INFO] [stdout]      |
[INFO] [stdout] 2132 |         fn abs(input: i32) -> i32;
[INFO] [stdout]      |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `Alaska` should have a snake case name
[INFO] [stdout]    --> src/main.rs:533:9
[INFO] [stdout]     |
[INFO] [stdout] 533 |     let Alaska = Coin::Quarter(UsState::Alaska);
[INFO] [stdout]     |         ^^^^^^ help: convert the identifier to snake case: `alaska`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: creating a shared reference to mutable static is discouraged
[INFO] [stdout]     --> src/main.rs:2148:38
[INFO] [stdout]      |
[INFO] [stdout] 2148 |     unsafe { println!("COUNTER: {}", COUNTER) }
[INFO] [stdout]      |                                      ^^^^^^^ shared reference to mutable static
[INFO] [stdout]      |
[INFO] [stdout]      = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
[INFO] [stdout]      = note: shared references to mutable statics are dangerous; it's undefined behavior if the static is mutated or if a mutable reference is created for it while the shared reference lives
[INFO] [stdout]      = note: `#[warn(static_mut_refs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.41s
[INFO] running `Command { std: "docker" "inspect" "e6fa135eeb1fe0eb4a17072ada062f4d58b3f41473cce5f96a484ce8313c0ba4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e6fa135eeb1fe0eb4a17072ada062f4d58b3f41473cce5f96a484ce8313c0ba4", kill_on_drop: false }`
[INFO] [stdout] e6fa135eeb1fe0eb4a17072ada062f4d58b3f41473cce5f96a484ce8313c0ba4