[INFO] cloning repository https://github.com/chinaxxren/lesson
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/chinaxxren/lesson" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchinaxxren%2Flesson", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchinaxxren%2Flesson'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ac0729489a0a94fb7e97bb134bd55a85970214bb
[INFO] checking chinaxxren/lesson against try#8c500c7cefd54fd11d57295f3771d576be9ee415 for pr-145113
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchinaxxren%2Flesson" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/chinaxxren/lesson
[INFO] finished tweaking git repo https://github.com/chinaxxren/lesson
[INFO] tweaked toml for git repo https://github.com/chinaxxren/lesson written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/chinaxxren/lesson on toolchain 8c500c7cefd54fd11d57295f3771d576be9ee415
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+8c500c7cefd54fd11d57295f3771d576be9ee415" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/chinaxxren/lesson 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" "+8c500c7cefd54fd11d57295f3771d576be9ee415" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/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:ae6f63d130afcfff7f91f5ba9fdb2a74d52830289c6a2ea2d23a94dcfb480a0d" "/opt/rustwide/cargo-home/bin/cargo" "+8c500c7cefd54fd11d57295f3771d576be9ee415" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2c181f5d876908efb0ec71cd2f057e76ce9feec7695350e23fe48829125494a3
[INFO] running `Command { std: "docker" "start" "-a" "2c181f5d876908efb0ec71cd2f057e76ce9feec7695350e23fe48829125494a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2c181f5d876908efb0ec71cd2f057e76ce9feec7695350e23fe48829125494a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2c181f5d876908efb0ec71cd2f057e76ce9feec7695350e23fe48829125494a3", kill_on_drop: false }`
[INFO] [stdout] 2c181f5d876908efb0ec71cd2f057e76ce9feec7695350e23fe48829125494a3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:ae6f63d130afcfff7f91f5ba9fdb2a74d52830289c6a2ea2d23a94dcfb480a0d" "/opt/rustwide/cargo-home/bin/cargo" "+8c500c7cefd54fd11d57295f3771d576be9ee415" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e6605a8c6819e02b4582642299ed5b63fabcd62f3e1aa9672832105d0e0538cc
[INFO] running `Command { std: "docker" "start" "-a" "e6605a8c6819e02b4582642299ed5b63fabcd62f3e1aa9672832105d0e0538cc", kill_on_drop: false }`
[INFO] [stderr]     Checking lesson v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::ptr::addr_of`
[INFO] [stdout]  --> src/lesson_four.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ptr::addr_of;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ptr::addr_of`
[INFO] [stdout]  --> src/lesson_four.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ptr::addr_of;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `str`
[INFO] [stdout]   --> src/lesson_two.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let str = "hello";
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]   --> src/lesson_two.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let reference_to_nothing = dangle();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_to_nothing`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/lesson_two.rs:49:13
[INFO] [stdout]    |
[INFO] [stdout] 49 |         let r1 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> src/lesson_two.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let r2 = &mut s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/lesson_two.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let r1 = &mut s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `str`
[INFO] [stdout]   --> src/lesson_two.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let str = "hello";
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `reference_to_nothing`
[INFO] [stdout]   --> src/lesson_two.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let reference_to_nothing = dangle();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_to_nothing`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/lesson_two.rs:49:13
[INFO] [stdout]    |
[INFO] [stdout] 49 |         let r1 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> src/lesson_two.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let r2 = &mut s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/lesson_two.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let r1 = &mut s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/lesson_five.rs:53:19
[INFO] [stdout]    |
[INFO] [stdout] 53 |     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
[INFO] [stdout]    |                   ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/lesson_one.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     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: `z`
[INFO] [stdout]   --> src/lesson_one.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     let z = "my new";
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]   --> src/lesson_one.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let s1 = gives_ownership();         // gives_ownership 将返回值
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/lesson_six.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     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: `v`
[INFO] [stdout]  --> src/lesson_six.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let v = vec![1, 2, 3];
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/lesson_five.rs:53:19
[INFO] [stdout]    |
[INFO] [stdout] 53 |     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
[INFO] [stdout]    |                   ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]   --> src/lesson_one.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     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: `z`
[INFO] [stdout]   --> src/lesson_one.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     let z = "my new";
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     let b = Cons(3, Box::new(a));
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 36 |     let b = Cons(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/lesson_rc.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let c = Cons(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: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let b = Cons(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/lesson_rc.rs:48:13
[INFO] [stdout]    |
[INFO] [stdout] 48 |         let c = Cons(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: `s1`
[INFO] [stdout]   --> src/lesson_one.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let s1 = gives_ownership();         // gives_ownership 将返回值
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/lesson_six.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     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: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_two.rs:6:15
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/lesson_six.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let v = vec![1, 2, 3];
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length` is never used
[INFO] [stdout]   --> src/lesson_two.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn calculate_length(s: &String) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson6` is never used
[INFO] [stdout]   --> src/lesson_two.rs:18:15
[INFO] [stdout]    |
[INFO] [stdout] 18 | pub(crate) fn lesson6() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `dangle` is never used
[INFO] [stdout]   --> src/lesson_two.rs:28:4
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn dangle() -> String {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson5` is never used
[INFO] [stdout]   --> src/lesson_two.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub(crate) fn lesson5() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson4` is never used
[INFO] [stdout]   --> src/lesson_two.rs:45:15
[INFO] [stdout]    |
[INFO] [stdout] 45 | pub(crate) fn lesson4() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_two.rs:55:15
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_two.rs:66:15
[INFO] [stdout]    |
[INFO] [stdout] 66 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `change` is never used
[INFO] [stdout]   --> src/lesson_two.rs:72:4
[INFO] [stdout]    |
[INFO] [stdout] 72 | fn change(some_string: &mut String) {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]  --> src/lesson_three.rs:5:15
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub(crate) fn lesson3() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_three.rs:14:15
[INFO] [stdout]    |
[INFO] [stdout] 14 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `first_word` is never used
[INFO] [stdout]   --> src/lesson_three.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn first_word(s: &String) -> &str {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_three.rs:37:15
[INFO] [stdout]    |
[INFO] [stdout] 37 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_four.rs:20:15
[INFO] [stdout]    |
[INFO] [stdout] 20 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_four.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `build_user` is never used
[INFO] [stdout]   --> src/lesson_four.rs:45:4
[INFO] [stdout]    |
[INFO] [stdout] 45 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_four.rs:54:15
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `User` is never constructed
[INFO] [stdout]   --> src/lesson_four.rs:67:8
[INFO] [stdout]    |
[INFO] [stdout] 67 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_five.rs:20:15
[INFO] [stdout]    |
[INFO] [stdout] 20 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_str` is never used
[INFO] [stdout]   --> src/lesson_five.rs:43:4
[INFO] [stdout]    |
[INFO] [stdout] 43 | fn print_str(string: String){
[INFO] [stdout]    |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/lesson_five.rs:47:8
[INFO] [stdout]    |
[INFO] [stdout] 47 | struct Rectangle {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `square` is never used
[INFO] [stdout]   --> src/lesson_five.rs:59:8
[INFO] [stdout]    |
[INFO] [stdout] 58 | impl Rectangle {
[INFO] [stdout]    | -------------- associated function in this implementation
[INFO] [stdout] 59 |     fn square(size: u32) -> Self {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `area` and `can_hold` are never used
[INFO] [stdout]   --> src/lesson_five.rs:68:8
[INFO] [stdout]    |
[INFO] [stdout] 67 | impl Rectangle {
[INFO] [stdout]    | -------------- methods in this implementation
[INFO] [stdout] 68 |     fn area(&self) -> u32 {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 72 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `area` is never used
[INFO] [stdout]   --> src/lesson_five.rs:77:4
[INFO] [stdout]    |
[INFO] [stdout] 77 | fn area(rectangle: &Rectangle) -> u32 {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_one.rs:5:15
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_one.rs:28:15
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `takes_ownership` is never used
[INFO] [stdout]   --> src/lesson_one.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn takes_ownership(some_string: String) { // some_string 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `makes_copy` is never used
[INFO] [stdout]   --> src/lesson_one.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn makes_copy(some_integer: i32) { // some_integer 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_one.rs:51:15
[INFO] [stdout]    |
[INFO] [stdout] 51 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `gives_ownership` is never used
[INFO] [stdout]   --> src/lesson_one.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn gives_ownership() -> String {             // gives_ownership 会将
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `takes_and_gives_back` is never used
[INFO] [stdout]   --> src/lesson_one.rs:75:4
[INFO] [stdout]    |
[INFO] [stdout] 75 | fn takes_and_gives_back(a_string: String) -> String { // a_string 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_six.rs:3:15
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `level` and `announce_and_return_part` are never used
[INFO] [stdout]   --> src/lesson_six.rs:50:12
[INFO] [stdout]    |
[INFO] [stdout] 49 |     impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]    |     ----------------------------- methods in this implementation
[INFO] [stdout] 50 |         fn level(&self) -> i32 {
[INFO] [stdout]    |            ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 54 |         fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/lesson_box.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 | enum List {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_box.rs:25:15
[INFO] [stdout]    |
[INFO] [stdout] 25 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]  --> src/MyBox.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct MyBox<T>(T);
[INFO] [stdout]   |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/MyBox.rs:6:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | impl<T> MyBox<T> {
[INFO] [stdout]   | ---------------- associated function in this implementation
[INFO] [stdout] 6 |     fn new(x: T) -> MyBox<T> {
[INFO] [stdout]   |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]  --> src/lesson_rc.rs:8:6
[INFO] [stdout]   |
[INFO] [stdout] 8 | enum List {
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:13:15
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `RcList` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:22:6
[INFO] [stdout]    |
[INFO] [stdout] 22 | enum RcList {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:29:15
[INFO] [stdout]    |
[INFO] [stdout] 29 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:40:15
[INFO] [stdout]    |
[INFO] [stdout] 40 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Messenger` is never used
[INFO] [stdout]  --> src/lesson_refcell.rs:9:11
[INFO] [stdout]   |
[INFO] [stdout] 9 | pub trait Messenger {
[INFO] [stdout]   |           ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `LimitTracker` is never constructed
[INFO] [stdout]   --> src/lesson_refcell.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub struct LimitTracker<'a, T: Messenger> {
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `set_value` are never used
[INFO] [stdout]   --> src/lesson_refcell.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 19 | / impl<'a, T> LimitTracker<'a, T>
[INFO] [stdout] 20 | | where
[INFO] [stdout] 21 | |     T: Messenger,
[INFO] [stdout]    | |_________________- associated items in this implementation
[INFO] [stdout] 22 |   {
[INFO] [stdout] 23 |       pub fn new(messenger: &'a T, max: usize) -> LimitTracker<'a, T> {
[INFO] [stdout]    |              ^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |       pub fn set_value(&mut self, value: usize) {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/lesson_refcell.rs:53:10
[INFO] [stdout]    |
[INFO] [stdout] 53 |     Cons(Rc<RefCell<i32>>, Rc<RefList>),
[INFO] [stdout]    |     ---- ^^^^^^^^^^^^^^^^  ^^^^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `RefList` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 53 -     Cons(Rc<RefCell<i32>>, Rc<RefList>),
[INFO] [stdout] 53 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: module `MyBox` should have a snake case name
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | mod MyBox;
[INFO] [stdout]   |     ^^^^^ help: convert the identifier to snake case: `my_box`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     let b = Cons(3, Box::new(a));
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 36 |     let b = Cons(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/lesson_rc.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let c = Cons(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: `b`
[INFO] [stdout]   --> src/lesson_rc.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let b = Cons(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/lesson_rc.rs:48:13
[INFO] [stdout]    |
[INFO] [stdout] 48 |         let c = Cons(4, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_two.rs:6:15
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `calculate_length` is never used
[INFO] [stdout]   --> src/lesson_two.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn calculate_length(s: &String) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson6` is never used
[INFO] [stdout]   --> src/lesson_two.rs:18:15
[INFO] [stdout]    |
[INFO] [stdout] 18 | pub(crate) fn lesson6() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `dangle` is never used
[INFO] [stdout]   --> src/lesson_two.rs:28:4
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn dangle() -> String {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson5` is never used
[INFO] [stdout]   --> src/lesson_two.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub(crate) fn lesson5() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson4` is never used
[INFO] [stdout]   --> src/lesson_two.rs:45:15
[INFO] [stdout]    |
[INFO] [stdout] 45 | pub(crate) fn lesson4() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_two.rs:55:15
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_two.rs:66:15
[INFO] [stdout]    |
[INFO] [stdout] 66 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `change` is never used
[INFO] [stdout]   --> src/lesson_two.rs:72:4
[INFO] [stdout]    |
[INFO] [stdout] 72 | fn change(some_string: &mut String) {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]  --> src/lesson_three.rs:5:15
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub(crate) fn lesson3() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_three.rs:14:15
[INFO] [stdout]    |
[INFO] [stdout] 14 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `first_word` is never used
[INFO] [stdout]   --> src/lesson_three.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn first_word(s: &String) -> &str {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_three.rs:37:15
[INFO] [stdout]    |
[INFO] [stdout] 37 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_four.rs:20:15
[INFO] [stdout]    |
[INFO] [stdout] 20 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_four.rs:33:15
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `build_user` is never used
[INFO] [stdout]   --> src/lesson_four.rs:45:4
[INFO] [stdout]    |
[INFO] [stdout] 45 | fn build_user(email: String, username: String) -> User {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_four.rs:54:15
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `User` is never constructed
[INFO] [stdout]   --> src/lesson_four.rs:67:8
[INFO] [stdout]    |
[INFO] [stdout] 67 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_five.rs:20:15
[INFO] [stdout]    |
[INFO] [stdout] 20 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_str` is never used
[INFO] [stdout]   --> src/lesson_five.rs:43:4
[INFO] [stdout]    |
[INFO] [stdout] 43 | fn print_str(string: String){
[INFO] [stdout]    |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/lesson_five.rs:47:8
[INFO] [stdout]    |
[INFO] [stdout] 47 | struct Rectangle {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `square` is never used
[INFO] [stdout]   --> src/lesson_five.rs:59:8
[INFO] [stdout]    |
[INFO] [stdout] 58 | impl Rectangle {
[INFO] [stdout]    | -------------- associated function in this implementation
[INFO] [stdout] 59 |     fn square(size: u32) -> Self {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `area` and `can_hold` are never used
[INFO] [stdout]   --> src/lesson_five.rs:68:8
[INFO] [stdout]    |
[INFO] [stdout] 67 | impl Rectangle {
[INFO] [stdout]    | -------------- methods in this implementation
[INFO] [stdout] 68 |     fn area(&self) -> u32 {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 72 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `area` is never used
[INFO] [stdout]   --> src/lesson_five.rs:77:4
[INFO] [stdout]    |
[INFO] [stdout] 77 | fn area(rectangle: &Rectangle) -> u32 {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_one.rs:5:15
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_one.rs:28:15
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `takes_ownership` is never used
[INFO] [stdout]   --> src/lesson_one.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn takes_ownership(some_string: String) { // some_string 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `makes_copy` is never used
[INFO] [stdout]   --> src/lesson_one.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn makes_copy(some_integer: i32) { // some_integer 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_one.rs:51:15
[INFO] [stdout]    |
[INFO] [stdout] 51 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `gives_ownership` is never used
[INFO] [stdout]   --> src/lesson_one.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn gives_ownership() -> String {             // gives_ownership 会将
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `takes_and_gives_back` is never used
[INFO] [stdout]   --> src/lesson_one.rs:75:4
[INFO] [stdout]    |
[INFO] [stdout] 75 | fn takes_and_gives_back(a_string: String) -> String { // a_string 进入作用域
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]  --> src/lesson_six.rs:3:15
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub(crate) fn lesson1() {
[INFO] [stdout]   |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `level` and `announce_and_return_part` are never used
[INFO] [stdout]   --> src/lesson_six.rs:50:12
[INFO] [stdout]    |
[INFO] [stdout] 49 |     impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]    |     ----------------------------- methods in this implementation
[INFO] [stdout] 50 |         fn level(&self) -> i32 {
[INFO] [stdout]    |            ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 54 |         fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/lesson_box.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 | enum List {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_box.rs:25:15
[INFO] [stdout]    |
[INFO] [stdout] 25 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]  --> src/MyBox.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct MyBox<T>(T);
[INFO] [stdout]   |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/MyBox.rs:6:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | impl<T> MyBox<T> {
[INFO] [stdout]   | ---------------- associated function in this implementation
[INFO] [stdout] 6 |     fn new(x: T) -> MyBox<T> {
[INFO] [stdout]   |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]  --> src/lesson_rc.rs:8:6
[INFO] [stdout]   |
[INFO] [stdout] 8 | enum List {
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson1` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:13:15
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub(crate) fn lesson1() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `RcList` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:22:6
[INFO] [stdout]    |
[INFO] [stdout] 22 | enum RcList {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson2` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:29:15
[INFO] [stdout]    |
[INFO] [stdout] 29 | pub(crate) fn lesson2() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `lesson3` is never used
[INFO] [stdout]   --> src/lesson_rc.rs:40:15
[INFO] [stdout]    |
[INFO] [stdout] 40 | pub(crate) fn lesson3() {
[INFO] [stdout]    |               ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Messenger` is never used
[INFO] [stdout]  --> src/lesson_refcell.rs:9:11
[INFO] [stdout]   |
[INFO] [stdout] 9 | pub trait Messenger {
[INFO] [stdout]   |           ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `LimitTracker` is never constructed
[INFO] [stdout]   --> src/lesson_refcell.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub struct LimitTracker<'a, T: Messenger> {
[INFO] [stdout]    |            ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `set_value` are never used
[INFO] [stdout]   --> src/lesson_refcell.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 19 | / impl<'a, T> LimitTracker<'a, T>
[INFO] [stdout] 20 | | where
[INFO] [stdout] 21 | |     T: Messenger,
[INFO] [stdout]    | |_________________- associated items in this implementation
[INFO] [stdout] 22 |   {
[INFO] [stdout] 23 |       pub fn new(messenger: &'a T, max: usize) -> LimitTracker<'a, T> {
[INFO] [stdout]    |              ^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |       pub fn set_value(&mut self, value: usize) {
[INFO] [stdout]    |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/lesson_refcell.rs:53:10
[INFO] [stdout]    |
[INFO] [stdout] 53 |     Cons(Rc<RefCell<i32>>, Rc<RefList>),
[INFO] [stdout]    |     ---- ^^^^^^^^^^^^^^^^  ^^^^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `RefList` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 53 -     Cons(Rc<RefCell<i32>>, Rc<RefList>),
[INFO] [stdout] 53 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: module `MyBox` should have a snake case name
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | mod MyBox;
[INFO] [stdout]   |     ^^^^^ help: convert the identifier to snake case: `my_box`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.24s
[INFO] running `Command { std: "docker" "inspect" "e6605a8c6819e02b4582642299ed5b63fabcd62f3e1aa9672832105d0e0538cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e6605a8c6819e02b4582642299ed5b63fabcd62f3e1aa9672832105d0e0538cc", kill_on_drop: false }`
[INFO] [stdout] e6605a8c6819e02b4582642299ed5b63fabcd62f3e1aa9672832105d0e0538cc