[INFO] cloning repository https://github.com/rust-kotlin/rust_projects
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/rust-kotlin/rust_projects" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-kotlin%2Frust_projects", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-kotlin%2Frust_projects'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d0a794ba59af115d7be1e19040c7aaeb5a13715c
[INFO] checking rust-kotlin/rust_projects against try#24e1a22664233bce1f9b5dc6eee7c1f74327e28c for pr-159343
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-kotlin%2Frust_projects" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/rust-kotlin/rust_projects
[INFO] finished tweaking git repo https://github.com/rust-kotlin/rust_projects
[INFO] tweaked toml for git repo https://github.com/rust-kotlin/rust_projects written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/rust-kotlin/rust_projects on toolchain 24e1a22664233bce1f9b5dc6eee7c1f74327e28c
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+24e1a22664233bce1f9b5dc6eee7c1f74327e28c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/rust-kotlin/rust_projects 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" "+24e1a22664233bce1f9b5dc6eee7c1f74327e28c" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3d5ced03c013a94a2f102a4510f48a6e9184255caf5fd8244f58017bde7f5210" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c
[INFO] running `Command { std: "docker" "start" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c" "/opt/rustwide/cargo-home/bin/cargo" "+24e1a22664233bce1f9b5dc6eee7c1f74327e28c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-w" "/opt/rustwide/workdir" "--user" "0:0" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c" "/opt/rustwide/cargo-home/bin/cargo" "+24e1a22664233bce1f9b5dc6eee7c1f74327e28c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.137
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking colored v2.0.0
[INFO] [stderr]     Checking rust_projects v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `fourth`
[INFO] [stdout]   --> src/bin/07question-operator.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let fourth = get_fourth(&my_vec);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_fourth`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Cell` and `RefCell`
[INFO] [stdout]  --> src/bin/16type-aliases.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::{Cell, RefCell};
[INFO] [stdout]   |                 ^^^^  ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `fourth`
[INFO] [stdout]   --> src/bin/07question-operator.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let fourth = get_fourth(&my_vec);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_fourth`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `book`
[INFO] [stdout]   --> src/bin/17todo-macro.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn get_book(book: &Book) -> Option<String> {
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_book`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `book`
[INFO] [stdout]   --> src/bin/17todo-macro.rs:14:16
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn delete_book(book: Book) -> Result<(), String> {
[INFO] [stdout]    |                ^^^^ help: if this is intentional, prefix it with an underscore: `_book`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Book` is never constructed
[INFO] [stdout]  --> src/bin/17todo-macro.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | struct Book {} // Okay, first I need a book struct.
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `SoftCover` is never constructed
[INFO] [stdout]  --> src/bin/17todo-macro.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | enum BookType {
[INFO] [stdout]   |      -------- variant in this enum
[INFO] [stdout] ...
[INFO] [stdout] 7 |     SoftCover,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `get_book` is never used
[INFO] [stdout]   --> src/bin/17todo-macro.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn get_book(book: &Book) -> Option<String> {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `delete_book` is never used
[INFO] [stdout]   --> src/bin/17todo-macro.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn delete_book(book: Book) -> Result<(), String> {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `CharacterVec` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:2:6
[INFO] [stdout]   |
[INFO] [stdout] 2 | type CharacterVec = Vec<char>;
[INFO] [stdout]   |      ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `SkipFourTakeFive` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 | type SkipFourTakeFive<'a> = std::iter::Take<std::iter::Skip<std::slice::Iter<'a, char>>>;
[INFO] [stdout]   |      ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `returns` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's named elsewhere is confusing
[INFO] [stdout]  --> src/bin/16type-aliases.rs:5:44
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive {
[INFO] [stdout]   |                        --                  ^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]   |                        |
[INFO] [stdout]   |                        the lifetime is named here
[INFO] [stdout]   |
[INFO] [stdout]   = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]   = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: consistently use `'a`
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive<'a> {
[INFO] [stdout]   |                                                            ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `book`
[INFO] [stdout]   --> src/bin/17todo-macro.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn get_book(book: &Book) -> Option<String> {
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_book`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `book`
[INFO] [stdout]   --> src/bin/17todo-macro.rs:14:16
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn delete_book(book: Book) -> Result<(), String> {
[INFO] [stdout]    |                ^^^^ help: if this is intentional, prefix it with an underscore: `_book`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Book` is never constructed
[INFO] [stdout]  --> src/bin/17todo-macro.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | struct Book {} // Okay, first I need a book struct.
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `SoftCover` is never constructed
[INFO] [stdout]  --> src/bin/17todo-macro.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | enum BookType {
[INFO] [stdout]   |      -------- variant in this enum
[INFO] [stdout] ...
[INFO] [stdout] 7 |     SoftCover,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `get_book` is never used
[INFO] [stdout]   --> src/bin/17todo-macro.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn get_book(book: &Book) -> Option<String> {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `delete_book` is never used
[INFO] [stdout]   --> src/bin/17todo-macro.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn delete_book(book: Book) -> Result<(), String> {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::path::Components`
[INFO] [stdout]  --> src/bin/28trait-object.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::path::Components;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `forever` is never used
[INFO] [stdout]   --> src/bin/23generics.rs:31:4
[INFO] [stdout]    |
[INFO] [stdout] 31 | fn forever() -> ! {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `canada_cities`
[INFO] [stdout]   --> src/bin/18reference-counter.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let canada_cities = CityData {
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_canada_cities`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `my_number` is assigned to, but never used
[INFO] [stdout]  --> src/bin/12debug-macro.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut my_number = dbg!(9);
[INFO] [stdout]   |         ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_my_number` instead
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `forever` is never used
[INFO] [stdout]   --> src/bin/23generics.rs:31:4
[INFO] [stdout]    |
[INFO] [stdout] 31 | fn forever() -> ! {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Cell` and `RefCell`
[INFO] [stdout]  --> src/bin/16type-aliases.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::{Cell, RefCell};
[INFO] [stdout]   |                 ^^^^  ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_owner`
[INFO] [stdout]   --> src/bin/18reference-counter.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     let new_owner = calgary.city_history.clone();
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_owner`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `double_vec`
[INFO] [stdout]   --> src/bin/12debug-macro.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let double_vec = new_vec
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_double_vec`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `population` is never read
[INFO] [stdout]  --> src/bin/18reference-counter.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct City {
[INFO] [stdout]   |        ---- field in this struct
[INFO] [stdout] 5 |     name: String,
[INFO] [stdout] 6 |     population: u32,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `City` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `names` and `histories` are never read
[INFO] [stdout]   --> src/bin/18reference-counter.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct CityData {
[INFO] [stdout]    |        -------- fields in this struct
[INFO] [stdout] 12 |     names: Vec<String>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 13 |     histories: Vec<Rc<String>>, // A Vec of Strings inside Rcs
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `CityData` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `my_number` is never read
[INFO] [stdout]  --> src/bin/12debug-macro.rs:4:10
[INFO] [stdout]   |
[INFO] [stdout] 4 |     dbg!(my_number += 10);
[INFO] [stdout]   |          ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout]   = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `CharacterVec` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:2:6
[INFO] [stdout]   |
[INFO] [stdout] 2 | type CharacterVec = Vec<char>;
[INFO] [stdout]   |      ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `SkipFourTakeFive` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 | type SkipFourTakeFive<'a> = std::iter::Take<std::iter::Skip<std::slice::Iter<'a, char>>>;
[INFO] [stdout]   |      ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `returns` is never used
[INFO] [stdout]  --> src/bin/16type-aliases.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's named elsewhere is confusing
[INFO] [stdout]  --> src/bin/16type-aliases.rs:5:44
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive {
[INFO] [stdout]   |                        --                  ^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]   |                        |
[INFO] [stdout]   |                        the lifetime is named here
[INFO] [stdout]   |
[INFO] [stdout]   = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]   = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: consistently use `'a`
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn returns<'a>(input: &'a CharacterVec) -> SkipFourTakeFive<'a> {
[INFO] [stdout]   |                                                            ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]   --> src/bin/04loop.rs:30:13
[INFO] [stdout]    |
[INFO] [stdout] 30 |             'second_loop: loop {
[INFO] [stdout]    |             ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_labels)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:67:9
[INFO] [stdout]    |
[INFO] [stdout] 67 |     let mut mutex_changer = my_mutex.lock().unwrap();
[INFO] [stdout]    |         ----^^^^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 |     let mut other_mutex_changer = my_mutex.try_lock(); // try to get the lock
[INFO] [stdout]    |         ----^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mutex_changer`
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:67:9
[INFO] [stdout]    |
[INFO] [stdout] 67 |     let mut mutex_changer = my_mutex.lock().unwrap();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutex_changer`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `company_name`, `model_name`, `screen_size`, `memory`, and `date_issued` are never read
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:8:5
[INFO] [stdout]    |
[INFO] [stdout]  7 | struct PhoneModel {
[INFO] [stdout]    |        ---------- fields in this struct
[INFO] [stdout]  8 |     company_name: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout]  9 |     model_name: String,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 10 |     screen_size: f32,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout] 11 |     memory: usize,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 12 |     date_issued: u32,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `id`, `year_registered`, and `username` are never read
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 16 | struct User {
[INFO] [stdout]    |        ---- fields in this struct
[INFO] [stdout] 17 |     id: u32,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 18 |     year_registered: u32,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 19 |     username: String,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `User` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:67:9
[INFO] [stdout]    |
[INFO] [stdout] 67 |     let mut mutex_changer = my_mutex.lock().unwrap();
[INFO] [stdout]    |         ----^^^^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 |     let mut other_mutex_changer = my_mutex.try_lock(); // try to get the lock
[INFO] [stdout]    |         ----^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mutex_changer`
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:67:9
[INFO] [stdout]    |
[INFO] [stdout] 67 |     let mut mutex_changer = my_mutex.lock().unwrap();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutex_changer`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `company_name`, `model_name`, `screen_size`, `memory`, and `date_issued` are never read
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:8:5
[INFO] [stdout]    |
[INFO] [stdout]  7 | struct PhoneModel {
[INFO] [stdout]    |        ---------- fields in this struct
[INFO] [stdout]  8 |     company_name: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout]  9 |     model_name: String,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 10 |     screen_size: f32,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout] 11 |     memory: usize,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 12 |     date_issued: u32,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `id`, `year_registered`, and `username` are never read
[INFO] [stdout]   --> src/bin/14interior-mutability.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 16 | struct User {
[INFO] [stdout]    |        ---- fields in this struct
[INFO] [stdout] 17 |     id: u32,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 18 |     year_registered: u32,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 19 |     username: String,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `User` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]   --> src/bin/04loop.rs:30:13
[INFO] [stdout]    |
[INFO] [stdout] 30 |             'second_loop: loop {
[INFO] [stdout]    |             ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_labels)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `array`
[INFO] [stdout]   --> src/bin/03struct-and-enum.rs:61:9
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let array = [String::from("666"), String::from("999")];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_array`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `FileDirectory` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct FileDirectory;
[INFO] [stdout]   |        ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Color` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | struct Color(u8, u8, u8);
[INFO] [stdout]   |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `SizeAndColor` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 | struct SizeAndColor {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `array`
[INFO] [stdout]   --> src/bin/03struct-and-enum.rs:61:9
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let array = [String::from("666"), String::from("999")];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_array`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `FileDirectory` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct FileDirectory;
[INFO] [stdout]   |        ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Color` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | struct Color(u8, u8, u8);
[INFO] [stdout]   |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `SizeAndColor` is never constructed
[INFO] [stdout]  --> src/bin/03struct-and-enum.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 | struct SizeAndColor {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/bin/20smart-pointer.rs:54:10
[INFO] [stdout]    |
[INFO] [stdout] 54 |     Cons(i32, Box<List>),
[INFO] [stdout]    |     ---- ^^^  ^^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[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] 54 -     Cons(i32, Box<List>),
[INFO] [stdout] 54 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/bin/20smart-pointer.rs:54:10
[INFO] [stdout]    |
[INFO] [stdout] 54 |     Cons(i32, Box<List>),
[INFO] [stdout]    |     ---- ^^^  ^^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[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] 54 -     Cons(i32, Box<List>),
[INFO] [stdout] 54 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::path::Components`
[INFO] [stdout]  --> src/bin/28trait-object.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::path::Components;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `my_number` is assigned to, but never used
[INFO] [stdout]  --> src/bin/12debug-macro.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut my_number = dbg!(9);
[INFO] [stdout]   |         ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_my_number` instead
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `double_vec`
[INFO] [stdout]   --> src/bin/12debug-macro.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let double_vec = new_vec
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_double_vec`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `my_number` is never read
[INFO] [stdout]  --> src/bin/12debug-macro.rs:4:10
[INFO] [stdout]   |
[INFO] [stdout] 4 |     dbg!(my_number += 10);
[INFO] [stdout]   |          ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout]   = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `canada_cities`
[INFO] [stdout]   --> src/bin/18reference-counter.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let canada_cities = CityData {
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_canada_cities`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_owner`
[INFO] [stdout]   --> src/bin/18reference-counter.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     let new_owner = calgary.city_history.clone();
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_owner`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `population` is never read
[INFO] [stdout]  --> src/bin/18reference-counter.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct City {
[INFO] [stdout]   |        ---- field in this struct
[INFO] [stdout] 5 |     name: String,
[INFO] [stdout] 6 |     population: u32,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `City` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `names` and `histories` are never read
[INFO] [stdout]   --> src/bin/18reference-counter.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct CityData {
[INFO] [stdout]    |        -------- fields in this struct
[INFO] [stdout] 12 |     names: Vec<String>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 13 |     histories: Vec<Rc<String>>, // A Vec of Strings inside Rcs
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `CityData` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.84s
[INFO] running `Command { std: "docker" "inspect" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c", kill_on_drop: false }`
[INFO] [stdout] 4d94706db8c38556e2b67cb808bf93f4bc214f6addb7d4f28e6797458f567f7c
