[INFO] cloning repository https://github.com/yaoliao/rust-study
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/yaoliao/rust-study" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyaoliao%2Frust-study", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyaoliao%2Frust-study'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7abfa2dbfdcb13c376f606fd36eefa13c68c71a4
[INFO] checking yaoliao/rust-study against master#a609fb45efad59dfd459c76e50899be9f0583b5a for pr-80579
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyaoliao%2Frust-study" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/yaoliao/rust-study on toolchain a609fb45efad59dfd459c76e50899be9f0583b5a
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/yaoliao/rust-study
[INFO] finished tweaking git repo https://github.com/yaoliao/rust-study
[INFO] tweaked toml for git repo https://github.com/yaoliao/rust-study written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/yaoliao/rust-study already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 02b8b266f474e4ea07670c02fec57896d479f4663a52ddba01fb1109c0e6d650
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "02b8b266f474e4ea07670c02fec57896d479f4663a52ddba01fb1109c0e6d650", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "02b8b266f474e4ea07670c02fec57896d479f4663a52ddba01fb1109c0e6d650", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "02b8b266f474e4ea07670c02fec57896d479f4663a52ddba01fb1109c0e6d650", kill_on_drop: false }`
[INFO] [stdout] 02b8b266f474e4ea07670c02fec57896d479f4663a52ddba01fb1109c0e6d650
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+a609fb45efad59dfd459c76e50899be9f0583b5a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 413313756ad1b7bf760ee92a7a7b41b4d1d91eeaedf126f1cb9693ececbce210
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "413313756ad1b7bf760ee92a7a7b41b4d1d91eeaedf126f1cb9693ececbce210", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]     Checking gimli v0.23.0
[INFO] [stderr]     Checking adler v0.2.3
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]     Checking rustc-demangle v0.1.18
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking object v0.22.0
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking smallvec v0.4.5
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]    Compiling miniz_oxide v0.4.3
[INFO] [stderr]     Checking addr2line v0.14.0
[INFO] [stderr]     Checking backtrace v0.3.55
[INFO] [stderr]     Checking error-chain v0.10.0
[INFO] [stderr]     Checking ferris-says v0.2.0
[INFO] [stderr]     Checking rust-study v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `soup`
[INFO] [stdout]   --> src/lib.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     let soup = back_of_house::Appetizer::Soup;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_soup`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `add`
[INFO] [stdout]  --> src/front_of_house.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn add() {
[INFO] [stdout]   |        ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `take_order`
[INFO] [stdout]   --> src/front_of_house.rs:11:12
[INFO] [stdout]    |
[INFO] [stdout] 11 |         fn take_order() {}
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `server_order`
[INFO] [stdout]   --> src/front_of_house.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 |         fn server_order() {}
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `take_payment`
[INFO] [stdout]   --> src/front_of_house.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 15 |         fn take_payment() {}
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `serve_order`
[INFO] [stdout]   --> src/lib.rs:29:4
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn serve_order() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fix_incorrect_order`
[INFO] [stdout]   --> src/lib.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 |     fn fix_incorrect_order() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `cook_order`
[INFO] [stdout]   --> src/lib.rs:37:8
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn cook_order() {}
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `seasonal_fruit`
[INFO] [stdout]   --> src/lib.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |         seasonal_fruit: String,
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Salad`
[INFO] [stdout]   --> src/lib.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |         Salad,
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `soup`
[INFO] [stdout]   --> src/lib.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     let soup = back_of_house::Appetizer::Soup;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_soup`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `add`
[INFO] [stdout]  --> src/front_of_house.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn add() {
[INFO] [stdout]   |        ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `take_order`
[INFO] [stdout]   --> src/front_of_house.rs:11:12
[INFO] [stdout]    |
[INFO] [stdout] 11 |         fn take_order() {}
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `server_order`
[INFO] [stdout]   --> src/front_of_house.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 |         fn server_order() {}
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `take_payment`
[INFO] [stdout]   --> src/front_of_house.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 15 |         fn take_payment() {}
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `serve_order`
[INFO] [stdout]   --> src/lib.rs:29:4
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn serve_order() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fix_incorrect_order`
[INFO] [stdout]   --> src/lib.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 |     fn fix_incorrect_order() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `cook_order`
[INFO] [stdout]   --> src/lib.rs:37:8
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn cook_order() {}
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `seasonal_fruit`
[INFO] [stdout]   --> src/lib.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |         seasonal_fruit: String,
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Salad`
[INFO] [stdout]   --> src/lib.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |         Salad,
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:29:5
[INFO] [stdout]    |
[INFO] [stdout] 29 |     /// 下面这段代码无法通过编译
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` on by default
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 30 |     /// 因为使用了 [move] 导致 x 的所有权被转移到了 闭包[equal_to_x] 中
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:31:5
[INFO] [stdout]    |
[INFO] [stdout] 31 |     /// 当下一行想去输出 x 的时候已经无法获取到所有权了
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]  --> src/unsafe_study/mod.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 |     /// 不安全的创建裸指针的方法
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]   |
[INFO] [stdout]   = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]    --> src/smart_pointer.rs:208:5
[INFO] [stdout]     |
[INFO] [stdout] 208 |     /// 下列代码无法编译通过。因为 x 是不可变的，所以无法可变的借用他
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]     |
[INFO] [stdout]     = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]    --> src/smart_pointer.rs:209:5
[INFO] [stdout]     |
[INFO] [stdout] 209 |     /// 借用规则的一个推论是当有一个不可变值时，不能可变地借用它
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]     |
[INFO] [stdout]     = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:31:5
[INFO] [stdout]    |
[INFO] [stdout] 31 |     /// 函数指针实现了所有三个闭包 trait（Fn、FnMut 和 FnOnce），所以总是可以在调用期望闭包的函数时传递函数指针作为参数。                                           ...
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:32:5
[INFO] [stdout]    |
[INFO] [stdout] 32 |     /// 倾向于编写使用泛型和闭包 trait 的函数，这样它就能接受函数或闭包作为参数。
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cmp::Ordering`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::cmp::Ordering;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rand::Rng`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use rand::Rng;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/string.rs:43:5
[INFO] [stdout]    |
[INFO] [stdout] 43 | /     /// UTF-8编码时 一个汉字字符储存需要3到4个字节,所以 0.。1 运行会直接报错！！！！！！！
[INFO] [stdout] 44 | |     /// let c = &str[0..1];
[INFO] [stdout] 45 | |     /// println!("{}", c);
[INFO] [stdout]    | |__________________________^
[INFO] [stdout] 46 | 
[INFO] [stdout] 47 |       let chars = str.chars();
[INFO] [stdout]    |       ------------------------ rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/collection.rs:27:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | /     /// 获取了 vector 的第一个元素的不可变引用并尝试在 vector 末尾增加一个元素的时候，这是行不通的
[INFO] [stdout] 28 | |     /// let new_one = &vector[0];
[INFO] [stdout] 29 | |     /// vector.push(5);
[INFO] [stdout] 30 | |     /// println!("vec one :{}", new_one);
[INFO] [stdout]    | |_________________________________________^
[INFO] [stdout] 31 | 
[INFO] [stdout] 32 |       let num = vec![100, 233, 1232];
[INFO] [stdout]    |       ------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | /     /// u32 实现了 Copy trait 的类型，其值可以拷贝进哈希 map
[INFO] [stdout] 12 | |     /// 但是 String 的所有权会被转移到 map 中，
[INFO] [stdout] 13 | |     /// let mut map: HashMap<String, u32> = HashMap::new();
[INFO] [stdout] 14 | |     /// map.insert(jack, 23); // jack 的所有权已经被转移
[INFO] [stdout]    | |________________________________________________________^
[INFO] [stdout] ...
[INFO] [stdout] 17 |       let key = vec![String::from("Jack"), String::from("Rose")];
[INFO] [stdout]    |       ----------------------------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     /// 必须使用 HashMap<_, _> 表明类型
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 20 |     let mut map: HashMap<_, _> = key.iter().zip(value.iter()).collect();
[INFO] [stdout]    |     -------------------------------------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:52:5
[INFO] [stdout]    |
[INFO] [stdout] 52 |     /// 根据旧值更新新值
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 53 |     let text = "hello world wonderful world";
[INFO] [stdout]    |     ----------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]   --> src/practice.rs:43:23
[INFO] [stdout]    |
[INFO] [stdout] 43 |     if len / 2 == 0 { (vec[len / 2 - 1] + vec[len / 2]) } else { vec[len / 2] }
[INFO] [stdout]    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fmt::Display`
[INFO] [stdout]  --> src/trait_study.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::fmt::Display;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/trait_study.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | /     /// 返回错误，只有泛型为 f32 的才定义了这个方法
[INFO] [stdout] 12 | |     /// println!("distance_from_origin: {}", p.distance_from_origin());
[INFO] [stdout]    | |_______________________________________________________________________^
[INFO] [stdout] 13 |       let p = Point { x: 20.0, y: 30.0 };
[INFO] [stdout]    |       ----------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 | /     /// 闭包捕获环境
[INFO] [stdout] 21 | |     /// 如果你希望强制闭包获取其使用的环境值的所有权，可以在参数列表前使用 [move] 关键字
[INFO] [stdout] 22 | |     /// 类似：let equal_to_x = move |z| z == x;
[INFO] [stdout]    | |_______________________________________________^
[INFO] [stdout] 23 |       let x = 4;
[INFO] [stdout]    |       ---------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/smart_pointer.rs:97:5
[INFO] [stdout]    |
[INFO] [stdout] 97 |     /// 变量以被创建时 [相反] 的顺序被丢弃
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 98 |     let c = CustomSmartPointer { data: String::from("my stuff") };
[INFO] [stdout]    |     -------------------------------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/concurrent/thread_study.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |         /// 可以将 drop 放在这里，因为 [move] 会将变量的所有权转移到闭包中
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 33 |         drop(vec);
[INFO] [stdout]    |         --------- rustdoc does not generate documentation for expressions
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:36:5
[INFO] [stdout]    |
[INFO] [stdout] 36 |       /// 元组结构体和元组结构体枚举成员,它们也被称为实现了闭包 trait 的函数指针，
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 37 | /     let list_of_statuses: Vec<Status> =
[INFO] [stdout] 38 | |         (0u32..20)
[INFO] [stdout] 39 | |             .map(Status::Value)
[INFO] [stdout] 40 | |             .collect();
[INFO] [stdout]    | |_______________________- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fmt::Formatter`
[INFO] [stdout]  --> src/unsafe_study/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::Formatter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/mod.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 34 |       /// 只能在 unsafe 上下文中 [解引用]
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 35 | /     unsafe {
[INFO] [stdout] 36 | |         println!("r1 is: {}", *r1);
[INFO] [stdout] 37 | |         println!("r2 is: {}", *r2);
[INFO] [stdout] 38 | |     }
[INFO] [stdout]    | |_____- rustdoc does not generate documentation for expressions
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/mod.rs:77:5
[INFO] [stdout]    |
[INFO] [stdout] 77 |       /// 通过 [extern] 关键字，来调用 C 的函数
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 78 | /     unsafe {
[INFO] [stdout] 79 | |         println!("Absolute value of -3 according to C: {}", abs(-3));
[INFO] [stdout] 80 | |     }
[INFO] [stdout]    | |_____- rustdoc does not generate documentation for expressions
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/unsafe_study/mod.rs:93:5
[INFO] [stdout]    |
[INFO] [stdout] 93 |       /// 读取或修改一个可变静态变量是不安全的
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 94 | /     unsafe {
[INFO] [stdout] 95 | |         COUNTER += 1;
[INFO] [stdout] 96 | |     }
[INFO] [stdout]    | |_____- rustdoc does not generate documentation for expressions
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `Point_v1` should have an upper camel case name
[INFO] [stdout]    --> src/unsafe_study/mod.rs:115:8
[INFO] [stdout]     |
[INFO] [stdout] 115 | struct Point_v1 {
[INFO] [stdout]     |        ^^^^^^^^ help: convert the identifier to upper camel case: `PointV1`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:29:5
[INFO] [stdout]    |
[INFO] [stdout] 29 |     /// 下面这段代码无法通过编译
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` on by default
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 30 |     /// 因为使用了 [move] 导致 x 的所有权被转移到了 闭包[equal_to_x] 中
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:31:5
[INFO] [stdout]    |
[INFO] [stdout] 31 |     /// 当下一行想去输出 x 的时候已经无法获取到所有权了
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]    |
[INFO] [stdout]    = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]  --> src/unsafe_study/mod.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 |     /// 不安全的创建裸指针的方法
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
[INFO] [stdout]   |
[INFO] [stdout]   = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cmp::Ordering`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::cmp::Ordering;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rand::Rng`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use rand::Rng;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/string.rs:43:5
[INFO] [stdout]    |
[INFO] [stdout] 43 | /     /// UTF-8编码时 一个汉字字符储存需要3到4个字节,所以 0.。1 运行会直接报错！！！！！！！
[INFO] [stdout] 44 | |     /// let c = &str[0..1];
[INFO] [stdout] 45 | |     /// println!("{}", c);
[INFO] [stdout]    | |__________________________^
[INFO] [stdout] 46 | 
[INFO] [stdout] 47 |       let chars = str.chars();
[INFO] [stdout]    |       ------------------------ rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/collection.rs:27:5
[INFO] [stdout]    |
[INFO] [stdout] 27 | /     /// 获取了 vector 的第一个元素的不可变引用并尝试在 vector 末尾增加一个元素的时候，这是行不通的
[INFO] [stdout] 28 | |     /// let new_one = &vector[0];
[INFO] [stdout] 29 | |     /// vector.push(5);
[INFO] [stdout] 30 | |     /// println!("vec one :{}", new_one);
[INFO] [stdout]    | |_________________________________________^
[INFO] [stdout] 31 | 
[INFO] [stdout] 32 |       let num = vec![100, 233, 1232];
[INFO] [stdout]    |       ------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | /     /// u32 实现了 Copy trait 的类型，其值可以拷贝进哈希 map
[INFO] [stdout] 12 | |     /// 但是 String 的所有权会被转移到 map 中，
[INFO] [stdout] 13 | |     /// let mut map: HashMap<String, u32> = HashMap::new();
[INFO] [stdout] 14 | |     /// map.insert(jack, 23); // jack 的所有权已经被转移
[INFO] [stdout]    | |________________________________________________________^
[INFO] [stdout] ...
[INFO] [stdout] 17 |       let key = vec![String::from("Jack"), String::from("Rose")];
[INFO] [stdout]    |       ----------------------------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     /// 必须使用 HashMap<_, _> 表明类型
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 20 |     let mut map: HashMap<_, _> = key.iter().zip(value.iter()).collect();
[INFO] [stdout]    |     -------------------------------------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/map.rs:52:5
[INFO] [stdout]    |
[INFO] [stdout] 52 |     /// 根据旧值更新新值
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 53 |     let text = "hello world wonderful world";
[INFO] [stdout]    |     ----------------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]   --> src/practice.rs:43:23
[INFO] [stdout]    |
[INFO] [stdout] 43 |     if len / 2 == 0 { (vec[len / 2 - 1] + vec[len / 2]) } else { vec[len / 2] }
[INFO] [stdout]    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fmt::Display`
[INFO] [stdout]  --> src/trait_study.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::fmt::Display;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/trait_study.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | /     /// 返回错误，只有泛型为 f32 的才定义了这个方法
[INFO] [stdout] 12 | |     /// println!("distance_from_origin: {}", p.distance_from_origin());
[INFO] [stdout]    | |_______________________________________________________________________^
[INFO] [stdout] 13 |       let p = Point { x: 20.0, y: 30.0 };
[INFO] [stdout]    |       ----------------------------------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/closure.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 | /     /// 闭包捕获环境
[INFO] [stdout] 21 | |     /// 如果你希望强制闭包获取其使用的环境值的所有权，可以在参数列表前使用 [move] 关键字
[INFO] [stdout] 22 | |     /// 类似：let equal_to_x = move |z| z == x;
[INFO] [stdout]    | |_______________________________________________^
[INFO] [stdout] 23 |       let x = 4;
[INFO] [stdout]    |       ---------- rustdoc does not generate documentation for statements
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ConsRc`, `NilRc`
[INFO] [stdout]  --> src/smart_pointer.rs:5:36
[INFO] [stdout]   |
[INFO] [stdout] 5 | use crate::smart_pointer::ListRc::{ConsRc, NilRc};
[INFO] [stdout]   |                                    ^^^^^^  ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Arc`, `Mutex`, `mpsc`
[INFO] [stdout]  --> src/concurrent/thread_study.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::sync::{Arc, mpsc, Mutex};
[INFO] [stdout]   |                 ^^^  ^^^^  ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fmt::Formatter`
[INFO] [stdout]  --> src/unsafe_study/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::Formatter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `Point_v1` should have an upper camel case name
[INFO] [stdout]    --> src/unsafe_study/mod.rs:115:8
[INFO] [stdout]     |
[INFO] [stdout] 115 | struct Point_v1 {
[INFO] [stdout]     |        ^^^^^^^^ help: convert the identifier to upper camel case: `PointV1`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_str`
[INFO] [stdout]   --> src/main.rs:86:9
[INFO] [stdout]    |
[INFO] [stdout] 86 |     let some_str = Some("hello");
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/main.rs:87:9
[INFO] [stdout]    |
[INFO] [stdout] 87 |     let none: Option<u32> = None;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]    --> src/main.rs:104:9
[INFO] [stdout]     |
[INFO] [stdout] 104 |     let mut count = 0;
[INFO] [stdout]     |         ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_count` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]    --> src/main.rs:107:14
[INFO] [stdout]     |
[INFO] [stdout] 107 |     } else { count += 1 }
[INFO] [stdout]     |              ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp` is never read
[INFO] [stdout]    --> src/main.rs:132:9
[INFO] [stdout]     |
[INFO] [stdout] 132 |     let mut tmp = 0;
[INFO] [stdout]     |         ^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/main.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |     for i in 2..n + 1 {
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_str`
[INFO] [stdout]  --> src/string.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let new_str = String::new();
[INFO] [stdout]   |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]  --> src/string.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     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/string.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     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/string.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let s = String::from("initial contents");
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/collection.rs:13:13
[INFO] [stdout]    |
[INFO] [stdout] 13 |         let v = vec![1, 2, 3];
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]   --> src/collection.rs:47:9
[INFO] [stdout]    |
[INFO] [stdout] 47 |     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: `len`
[INFO] [stdout]   --> src/practice.rs:26:19
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let (mut cnt, len, mut res) = (0, vec.len(), vec[0]);
[INFO] [stdout]    |                   ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let f = match f {
[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/error.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let f = match f {
[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/error.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let f = File::open("rust.txt").unwrap_or_else(|error| {
[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/error.rs:42:9
[INFO] [stdout]    |
[INFO] [stdout] 42 |     let f = File::open("rust.txt").unwrap();
[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/error.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |     let f = File::open("rust.txt").expect("can't open file rust.txt");
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/smart_pointer.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let b = Box::new(5);
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/collection.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let mut vector = vec![1, 2, 3]; // 利用 vec! 宏 来创建
[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: `some_str`
[INFO] [stdout]   --> src/main.rs:86:9
[INFO] [stdout]    |
[INFO] [stdout] 86 |     let some_str = Some("hello");
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/main.rs:87:9
[INFO] [stdout]    |
[INFO] [stdout] 87 |     let none: Option<u32> = None;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]    --> src/main.rs:104:9
[INFO] [stdout]     |
[INFO] [stdout] 104 |     let mut count = 0;
[INFO] [stdout]     |         ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_count` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]    --> src/main.rs:107:14
[INFO] [stdout]     |
[INFO] [stdout] 107 |     } else { count += 1 }
[INFO] [stdout]     |              ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp` is never read
[INFO] [stdout]    --> src/main.rs:132:9
[INFO] [stdout]     |
[INFO] [stdout] 132 |     let mut tmp = 0;
[INFO] [stdout]     |         ^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/main.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |     for i in 2..n + 1 {
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_str`
[INFO] [stdout]  --> src/string.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let new_str = String::new();
[INFO] [stdout]   |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]  --> src/string.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     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/string.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     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/string.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let s = String::from("initial contents");
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/collection.rs:13:13
[INFO] [stdout]    |
[INFO] [stdout] 13 |         let v = vec![1, 2, 3];
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]   --> src/collection.rs:47:9
[INFO] [stdout]    |
[INFO] [stdout] 47 |     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: `len`
[INFO] [stdout]   --> src/practice.rs:26:19
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let (mut cnt, len, mut res) = (0, vec.len(), vec[0]);
[INFO] [stdout]    |                   ^^^ help: if this is intentional, prefix it with an underscore: `_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let f = match f {
[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/error.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let f = match f {
[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/error.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let f = File::open("rust.txt").unwrap_or_else(|error| {
[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/error.rs:42:9
[INFO] [stdout]    |
[INFO] [stdout] 42 |     let f = File::open("rust.txt").unwrap();
[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/error.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |     let f = File::open("rust.txt").expect("can't open file rust.txt");
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]    --> src/closure.rs:130:9
[INFO] [stdout]     |
[INFO] [stdout] 130 |     let v1 = c.value(1);
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]    --> src/closure.rs:140:9
[INFO] [stdout]     |
[INFO] [stdout] 140 |     let v1 = c.value(&1);
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]    --> src/closure.rs:145:9
[INFO] [stdout]     |
[INFO] [stdout] 145 |     let r1 = cache.value(&"aa");
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/smart_pointer.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let b = Box::new(5);
[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/smart_pointer.rs:98:9
[INFO] [stdout]    |
[INFO] [stdout] 98 |     let c = CustomSmartPointer { data: String::from("my stuff") };
[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/smart_pointer.rs:99:9
[INFO] [stdout]    |
[INFO] [stdout] 99 |     let d = CustomSmartPointer { data: String::from("other stuff") };
[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/smart_pointer.rs:124:9
[INFO] [stdout]     |
[INFO] [stdout] 124 |     let b = ConsRc(3, Rc::clone(&a));
[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/smart_pointer.rs:127:13
[INFO] [stdout]     |
[INFO] [stdout] 127 |         let c = ConsRc(4, Rc::clone(&a));
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list_of_statuses`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let list_of_statuses: Vec<Status> =
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_list_of_statuses`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/iterator.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let mut v1_iter = v1.iter();
[INFO] [stdout]   |         ----^^^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `string_study`
[INFO] [stdout]  --> src/string.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn string_study() {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `my_collection`
[INFO] [stdout]  --> src/collection.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn my_collection() {
[INFO] [stdout]   |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `SpreadsheetCell`
[INFO] [stdout]   --> src/collection.rs:54:6
[INFO] [stdout]    |
[INFO] [stdout] 54 | enum SpreadsheetCell {
[INFO] [stdout]    |      ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `map_study`
[INFO] [stdout]  --> src/map.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn map_study() {
[INFO] [stdout]   |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `bubble_sort`
[INFO] [stdout]   --> src/practice.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn bubble_sort(vec: &mut Vec<u32>) {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v1`
[INFO] [stdout]   --> src/error.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn read_username_from_file_v1() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v2`
[INFO] [stdout]   --> src/error.rs:72:4
[INFO] [stdout]    |
[INFO] [stdout] 72 | fn read_username_from_file_v2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `notify_t_d_where`
[INFO] [stdout]    --> src/trait_study.rs:149:4
[INFO] [stdout]     |
[INFO] [stdout] 149 | fn notify_t_d_where<T>(item: T)
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `grep`
[INFO] [stdout]  --> src/mini_grep.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub fn grep() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Config`
[INFO] [stdout]   --> src/mini_grep.rs:24:16
[INFO] [stdout]    |
[INFO] [stdout] 24 |     pub struct Config {
[INFO] [stdout]    |                ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/mini_grep.rs:31:16
[INFO] [stdout]    |
[INFO] [stdout] 31 |         pub fn new(args: &[String]) -> Result<Config, &'static str> {
[INFO] [stdout]    |                ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `run`
[INFO] [stdout]   --> src/mini_grep.rs:44:12
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `search`
[INFO] [stdout]   --> src/mini_grep.rs:60:8
[INFO] [stdout]    |
[INFO] [stdout] 60 |     fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `search_case_insensitive`
[INFO] [stdout]   --> src/mini_grep.rs:70:8
[INFO] [stdout]    |
[INFO] [stdout] 70 |     fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `simulated_expensive_calculation`
[INFO] [stdout]   --> src/closure.rs:41:4
[INFO] [stdout]    |
[INFO] [stdout] 41 | fn simulated_expensive_calculation(intensity: u32) -> u32 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `CacheMap`
[INFO] [stdout]    --> src/closure.rs:105:8
[INFO] [stdout]     |
[INFO] [stdout] 105 | struct CacheMap<'a, T, V>
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]    --> src/closure.rs:113:8
[INFO] [stdout]     |
[INFO] [stdout] 113 |     fn new(calculation: T) -> CacheMap<'a, T, V> {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `value`
[INFO] [stdout]    --> src/closure.rs:120:8
[INFO] [stdout]     |
[INFO] [stdout] 120 |     fn value(&mut self, arg: &'a V) -> &'a V {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `iterator_study`
[INFO] [stdout]  --> src/iterator.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn iterator_study() {
[INFO] [stdout]   |        ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `shoes_in_my_size`
[INFO] [stdout]   --> src/iterator.rs:16:4
[INFO] [stdout]    |
[INFO] [stdout] 16 | fn shoes_in_my_size(shoes: Vec<Shoe>, size: u32) -> Vec<Shoe> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/iterator.rs:27:8
[INFO] [stdout]    |
[INFO] [stdout] 27 |     fn new() -> Counter {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `point`
[INFO] [stdout]  --> src/smart_pointer.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn point() {
[INFO] [stdout]   |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Cons`
[INFO] [stdout]   --> src/smart_pointer.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     Cons(i32, Box<List>),
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nil`
[INFO] [stdout]   --> src/smart_pointer.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     Nil,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/smart_pointer.rs:26:8
[INFO] [stdout]    |
[INFO] [stdout] 26 |     fn new(x: T) -> MyBox<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `hello`
[INFO] [stdout]   --> src/smart_pointer.rs:40:4
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn hello(name: &str) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `ListRc`
[INFO] [stdout]    --> src/smart_pointer.rs:112:6
[INFO] [stdout]     |
[INFO] [stdout] 112 | enum ListRc {
[INFO] [stdout]     |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `LimitTracker`
[INFO] [stdout]    --> src/smart_pointer.rs:139:12
[INFO] [stdout]     |
[INFO] [stdout] 139 | pub struct LimitTracker<'a, T: Messenger> {
[INFO] [stdout]     |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]    --> src/smart_pointer.rs:147:12
[INFO] [stdout]     |
[INFO] [stdout] 147 |     pub fn new(messenger: &T, max: usize) -> LimitTracker<T> {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `set_value`
[INFO] [stdout]    --> src/smart_pointer.rs:155:12
[INFO] [stdout]     |
[INFO] [stdout] 155 |     pub fn set_value(&mut self, value: usize) {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `add_one`
[INFO] [stdout]  --> src/unsafe_study/function_pointer.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn add_one(x: i32) -> i32 {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `do_twice`
[INFO] [stdout]  --> src/unsafe_study/function_pointer.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn do_twice(f: fn(i32) -> i32, arg: i32) -> i32 {
[INFO] [stdout]   |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `do_twice_v1`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn do_twice_v1<T>(f: T, arg: i32) -> i32
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `Status`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:15:6
[INFO] [stdout]    |
[INFO] [stdout] 15 | enum Status {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `returns_closure`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `unsafe_use`
[INFO] [stdout]  --> src/unsafe_study/mod.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn unsafe_use() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `dangerous`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:42:11
[INFO] [stdout]    |
[INFO] [stdout] 42 | unsafe fn dangerous() {}
[INFO] [stdout]    |           ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `split_at_mut`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:45:4
[INFO] [stdout]    |
[INFO] [stdout] 45 | fn split_at_mut(slice: &mut [i32], mid: usize) -> (&mut [i32], &mut [i32]) {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `abs`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:60:5
[INFO] [stdout]    |
[INFO] [stdout] 60 |     fn abs(input: i32) -> i32;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `MAX_POINTS`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:84:1
[INFO] [stdout]    |
[INFO] [stdout] 84 | const MAX_POINTS: u32 = 100_000;
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: static is never used: `HELLO_WORLD`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:87:1
[INFO] [stdout]    |
[INFO] [stdout] 87 | static HELLO_WORLD: &str = "Hello, world!";
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: static is never used: `COUNTER`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:88:1
[INFO] [stdout]    |
[INFO] [stdout] 88 | static mut COUNTER: u32 = 0;
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `never_type`
[INFO] [stdout]    --> src/unsafe_study/mod.rs:212:4
[INFO] [stdout]     |
[INFO] [stdout] 212 | fn never_type() {}
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib`
[INFO] [stdout]    --> src/main.rs:125:4
[INFO] [stdout]     |
[INFO] [stdout] 125 | fn fib(n: i32) -> i32 {
[INFO] [stdout]     |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib1`
[INFO] [stdout]    --> src/main.rs:142:4
[INFO] [stdout]     |
[INFO] [stdout] 142 | fn fib1(n: i32) -> i32 {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Quit`
[INFO] [stdout]    --> src/main.rs:181:5
[INFO] [stdout]     |
[INFO] [stdout] 181 |     Quit,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Move`
[INFO] [stdout]    --> src/main.rs:182:5
[INFO] [stdout]     |
[INFO] [stdout] 182 |     Move { x: i32, y: i32 },
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/collection.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let mut vector = vec![1, 2, 3]; // 利用 vec! 宏 来创建
[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: variant is never constructed: `ChangeColor`
[INFO] [stdout]    --> src/main.rs:184:5
[INFO] [stdout]     |
[INFO] [stdout] 184 |     ChangeColor(i32, i32, i32),
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alaska`
[INFO] [stdout]    --> src/main.rs:197:5
[INFO] [stdout]     |
[INFO] [stdout] 197 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Penny`
[INFO] [stdout]    --> src/main.rs:202:5
[INFO] [stdout]     |
[INFO] [stdout] 202 |     Penny,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]    --> src/main.rs:203:5
[INFO] [stdout]     |
[INFO] [stdout] 203 |     Nickel,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Dime`
[INFO] [stdout]    --> src/main.rs:204:5
[INFO] [stdout]     |
[INFO] [stdout] 204 |     Dime,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 93 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/iterator.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let mut v1_iter = v1.iter();
[INFO] [stdout]   |         ----^^^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/unsafe_study/mod.rs:200:9
[INFO] [stdout]     |
[INFO] [stdout] 200 |     let mut w = Wrapper(vec![String::from("hello"), String::from("world")]);
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `string_study`
[INFO] [stdout]  --> src/string.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn string_study() {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `my_collection`
[INFO] [stdout]  --> src/collection.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn my_collection() {
[INFO] [stdout]   |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `SpreadsheetCell`
[INFO] [stdout]   --> src/collection.rs:54:6
[INFO] [stdout]    |
[INFO] [stdout] 54 | enum SpreadsheetCell {
[INFO] [stdout]    |      ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `map_study`
[INFO] [stdout]  --> src/map.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn map_study() {
[INFO] [stdout]   |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `bubble_sort`
[INFO] [stdout]   --> src/practice.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn bubble_sort(vec: &mut Vec<u32>) {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v1`
[INFO] [stdout]   --> src/error.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn read_username_from_file_v1() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v2`
[INFO] [stdout]   --> src/error.rs:72:4
[INFO] [stdout]    |
[INFO] [stdout] 72 | fn read_username_from_file_v2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `notify_t_d_where`
[INFO] [stdout]    --> src/trait_study.rs:149:4
[INFO] [stdout]     |
[INFO] [stdout] 149 | fn notify_t_d_where<T>(item: T)
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `grep`
[INFO] [stdout]  --> src/mini_grep.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub fn grep() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Config`
[INFO] [stdout]   --> src/mini_grep.rs:24:16
[INFO] [stdout]    |
[INFO] [stdout] 24 |     pub struct Config {
[INFO] [stdout]    |                ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/mini_grep.rs:31:16
[INFO] [stdout]    |
[INFO] [stdout] 31 |         pub fn new(args: &[String]) -> Result<Config, &'static str> {
[INFO] [stdout]    |                ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `run`
[INFO] [stdout]   --> src/mini_grep.rs:44:12
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `simulated_expensive_calculation`
[INFO] [stdout]   --> src/closure.rs:41:4
[INFO] [stdout]    |
[INFO] [stdout] 41 | fn simulated_expensive_calculation(intensity: u32) -> u32 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Stop`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 17 |     Stop,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `returns_closure`
[INFO] [stdout]   --> src/unsafe_study/function_pointer.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `unsafe_use`
[INFO] [stdout]  --> src/unsafe_study/mod.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn unsafe_use() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `MAX_POINTS`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:84:1
[INFO] [stdout]    |
[INFO] [stdout] 84 | const MAX_POINTS: u32 = 100_000;
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: static is never used: `HELLO_WORLD`
[INFO] [stdout]   --> src/unsafe_study/mod.rs:87:1
[INFO] [stdout]    |
[INFO] [stdout] 87 | static HELLO_WORLD: &str = "Hello, world!";
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `never_type`
[INFO] [stdout]    --> src/unsafe_study/mod.rs:212:4
[INFO] [stdout]     |
[INFO] [stdout] 212 | fn never_type() {}
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib`
[INFO] [stdout]    --> src/main.rs:125:4
[INFO] [stdout]     |
[INFO] [stdout] 125 | fn fib(n: i32) -> i32 {
[INFO] [stdout]     |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib1`
[INFO] [stdout]    --> src/main.rs:142:4
[INFO] [stdout]     |
[INFO] [stdout] 142 | fn fib1(n: i32) -> i32 {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Quit`
[INFO] [stdout]    --> src/main.rs:181:5
[INFO] [stdout]     |
[INFO] [stdout] 181 |     Quit,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Move`
[INFO] [stdout]    --> src/main.rs:182:5
[INFO] [stdout]     |
[INFO] [stdout] 182 |     Move { x: i32, y: i32 },
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `ChangeColor`
[INFO] [stdout]    --> src/main.rs:184:5
[INFO] [stdout]     |
[INFO] [stdout] 184 |     ChangeColor(i32, i32, i32),
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alaska`
[INFO] [stdout]    --> src/main.rs:197:5
[INFO] [stdout]     |
[INFO] [stdout] 197 |     Alaska,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Penny`
[INFO] [stdout]    --> src/main.rs:202:5
[INFO] [stdout]     |
[INFO] [stdout] 202 |     Penny,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]    --> src/main.rs:203:5
[INFO] [stdout]     |
[INFO] [stdout] 203 |     Nickel,
[INFO] [stdout]     |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Dime`
[INFO] [stdout]    --> src/main.rs:204:5
[INFO] [stdout]     |
[INFO] [stdout] 204 |     Dime,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 86 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 14.39s
[INFO] running `Command { std: "docker" "inspect" "413313756ad1b7bf760ee92a7a7b41b4d1d91eeaedf126f1cb9693ececbce210", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "413313756ad1b7bf760ee92a7a7b41b4d1d91eeaedf126f1cb9693ececbce210", kill_on_drop: false }`
[INFO] [stdout] 413313756ad1b7bf760ee92a7a7b41b4d1d91eeaedf126f1cb9693ececbce210