[INFO] updating cached repository chrisp9/rust_exploration
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/chrisp9/rust_exploration
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/chrisp9/rust_exploration" "work/ex/pr-60162/sources/master#a850a426491e14186af2250549bf41256b5938d2/gh/chrisp9/rust_exploration"`
[INFO] [stderr] Cloning into 'work/ex/pr-60162/sources/master#a850a426491e14186af2250549bf41256b5938d2/gh/chrisp9/rust_exploration'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/chrisp9/rust_exploration" "work/ex/pr-60162/sources/try#06a150c7d11500b41499224f165e9de1de096768/gh/chrisp9/rust_exploration"`
[INFO] [stderr] Cloning into 'work/ex/pr-60162/sources/try#06a150c7d11500b41499224f165e9de1de096768/gh/chrisp9/rust_exploration'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 08c29e33beb024b8d3a51e551724e279bf8a4a9f
[INFO] sha for GitHub repo chrisp9/rust_exploration: 08c29e33beb024b8d3a51e551724e279bf8a4a9f
[INFO] validating manifest of chrisp9/rust_exploration on toolchain master#a850a426491e14186af2250549bf41256b5938d2
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+a850a426491e14186af2250549bf41256b5938d2-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of chrisp9/rust_exploration on toolchain try#06a150c7d11500b41499224f165e9de1de096768
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+06a150c7d11500b41499224f165e9de1de096768-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing chrisp9/rust_exploration
[INFO] finished frobbing chrisp9/rust_exploration
[INFO] frobbed toml for chrisp9/rust_exploration written to work/ex/pr-60162/sources/master#a850a426491e14186af2250549bf41256b5938d2/gh/chrisp9/rust_exploration/Cargo.toml
[INFO] started frobbing chrisp9/rust_exploration
[INFO] finished frobbing chrisp9/rust_exploration
[INFO] frobbed toml for chrisp9/rust_exploration written to work/ex/pr-60162/sources/try#06a150c7d11500b41499224f165e9de1de096768/gh/chrisp9/rust_exploration/Cargo.toml
[INFO] crate chrisp9/rust_exploration already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+a850a426491e14186af2250549bf41256b5938d2-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+06a150c7d11500b41499224f165e9de1de096768-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking chrisp9/rust_exploration against master#a850a426491e14186af2250549bf41256b5938d2 for pr-60162
[INFO] running `"docker" "create" "-v" "/mnt/crater-raid/crater/work/local/target-dirs/pr-60162/worker-1/master#a850a426491e14186af2250549bf41256b5938d2:/opt/crater/target:rw,Z" "-v" "/mnt/crater-raid/crater/work/ex/pr-60162/sources/master#a850a426491e14186af2250549bf41256b5938d2/gh/chrisp9/rust_exploration:/opt/crater/workdir:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+a850a426491e14186af2250549bf41256b5938d2-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] eca5f8c7e0c7166c4817ff8a2aa12b8ead07f1b104bc53d1c328f34e07f7164b
[INFO] running `"docker" "start" "-a" "eca5f8c7e0c7166c4817ff8a2aa12b8ead07f1b104bc53d1c328f34e07f7164b"`
[INFO] [stderr]     Checking rust_exploration v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `num`
[INFO] [stderr]    --> src/main.rs:177:45
[INFO] [stderr]     |
[INFO] [stderr] 177 |     let mut expensive_result = Cacher::new(|num| {
[INFO] [stderr]     |                                             ^^^ help: consider prefixing with an underscore: `_num`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `equal_to_x`
[INFO] [stderr]    --> src/main.rs:212:9
[INFO] [stderr]     |
[INFO] [stderr] 212 |     let equal_to_x = |z : u32| z == x;
[INFO] [stderr]     |         ^^^^^^^^^^ help: consider prefixing with an underscore: `_equal_to_x`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]    --> src/main.rs:213:9
[INFO] [stderr]     |
[INFO] [stderr] 213 |     let y = 4;
[INFO] [stderr]     |         ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `res`
[INFO] [stderr]    --> src/main.rs:229:9
[INFO] [stderr]     |
[INFO] [stderr] 229 |     let res: Vec<_> = v1.iter().map(|x| x + 1).collect();
[INFO] [stderr]     |         ^^^ help: consider prefixing with an underscore: `_res`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `total`
[INFO] [stderr]    --> src/main.rs:236:9
[INFO] [stderr]     |
[INFO] [stderr] 236 |     let total: i32 = v1_iter.sum();
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_total`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `item`
[INFO] [stderr]    --> src/main.rs:289:9
[INFO] [stderr]     |
[INFO] [stderr] 289 |     let item = map.get(&key).unwrap();
[INFO] [stderr]     |         ^^^^ help: consider prefixing with an underscore: `_item`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s3`
[INFO] [stderr]    --> src/main.rs:296:9
[INFO] [stderr]     |
[INFO] [stderr] 296 |     let s3 = s1 + &s2;
[INFO] [stderr]     |         ^^ help: consider prefixing with an underscore: `_s3`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `v`
[INFO] [stderr]    --> src/main.rs:306:9
[INFO] [stderr]     |
[INFO] [stderr] 306 |     let v: Vec<i32> = Vec::new();
[INFO] [stderr]     |         ^ help: consider prefixing with an underscore: `_v`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `third`
[INFO] [stderr]    --> src/main.rs:309:9
[INFO] [stderr]     |
[INFO] [stderr] 309 |     let third: &i32 = &v[2];
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_third`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_number`
[INFO] [stderr]    --> src/main.rs:372:9
[INFO] [stderr]     |
[INFO] [stderr] 372 |     let some_number = Some(5);
[INFO] [stderr]     |         ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_number`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_string`
[INFO] [stderr]    --> src/main.rs:373:9
[INFO] [stderr]     |
[INFO] [stderr] 373 |     let some_string = Some("A string");
[INFO] [stderr]     |         ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_string`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `absent_number`
[INFO] [stderr]    --> src/main.rs:375:9
[INFO] [stderr]     |
[INFO] [stderr] 375 |     let absent_number : Option<i32> = None;
[INFO] [stderr]     |         ^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_absent_number`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `rect3`
[INFO] [stderr]    --> src/main.rs:387:9
[INFO] [stderr]     |
[INFO] [stderr] 387 |     let rect3 = Rectangle {width: 60, height: 45};
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_rect3`
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `NewsArticle`
[INFO] [stderr]  --> src/news_aggregator/mod.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     pub struct NewsArticle {
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Tweet`
[INFO] [stderr]   --> src/news_aggregator/mod.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     pub struct Tweet {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Pair`
[INFO] [stderr]   --> src/main.rs:18:1
[INFO] [stderr]    |
[INFO] [stderr] 18 | struct Pair<T> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/main.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     fn new(x: T, y: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `cmp_display`
[INFO] [stderr]   --> src/main.rs:33:5
[INFO] [stderr]    |
[INFO] [stderr] 33 |     fn cmp_display(&self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `User`
[INFO] [stderr]   --> src/main.rs:42:1
[INFO] [stderr]    |
[INFO] [stderr] 42 | struct User {
[INFO] [stderr]    | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Rectangle`
[INFO] [stderr]   --> src/main.rs:49:1
[INFO] [stderr]    |
[INFO] [stderr] 49 | struct Rectangle {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `area`
[INFO] [stderr]   --> src/main.rs:55:5
[INFO] [stderr]    |
[INFO] [stderr] 55 |     fn area(&self) -> u32 {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `can_hold`
[INFO] [stderr]   --> src/main.rs:59:5
[INFO] [stderr]    |
[INFO] [stderr] 59 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `square`
[INFO] [stderr]   --> src/main.rs:63:5
[INFO] [stderr]    |
[INFO] [stderr] 63 |     fn square(size: u32) -> Rectangle {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `IpAddrKind`
[INFO] [stderr]   --> src/main.rs:68:1
[INFO] [stderr]    |
[INFO] [stderr] 68 | enum IpAddrKind {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `UsState`
[INFO] [stderr]   --> src/main.rs:74:1
[INFO] [stderr]    |
[INFO] [stderr] 74 | enum UsState {
[INFO] [stderr]    | ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Coin`
[INFO] [stderr]   --> src/main.rs:80:1
[INFO] [stderr]    |
[INFO] [stderr] 80 | enum Coin {
[INFO] [stderr]    | ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Message`
[INFO] [stderr]   --> src/main.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | enum Message {
[INFO] [stderr]    | ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `call`
[INFO] [stderr]   --> src/main.rs:95:5
[INFO] [stderr]    |
[INFO] [stderr] 95 |     fn call(&self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `largest`
[INFO] [stderr]    --> src/main.rs:100:2
[INFO] [stderr]     |
[INFO] [stderr] 100 |  fn largest<T : PartialOrd>(list: &[T]) -> &T {
[INFO] [stderr]     |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Point`
[INFO] [stderr]    --> src/main.rs:112:1
[INFO] [stderr]     |
[INFO] [stderr] 112 | struct Point<T> {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `shoes_in_my_size`
[INFO] [stderr]    --> src/main.rs:123:1
[INFO] [stderr]     |
[INFO] [stderr] 123 | fn shoes_in_my_size(shoes: Vec<Shoe>, shoe_size: u32) -> Vec<Shoe> {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `simulated_expensive_calculation`
[INFO] [stderr]    --> src/main.rs:204:1
[INFO] [stderr]     |
[INFO] [stderr] 204 | fn simulated_expensive_calculation(intensity: u32) -> u32 {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `closure_capturing_context`
[INFO] [stderr]    --> src/main.rs:210:1
[INFO] [stderr]     |
[INFO] [stderr] 210 | fn closure_capturing_context() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterators`
[INFO] [stderr]    --> src/main.rs:217:1
[INFO] [stderr]     |
[INFO] [stderr] 217 | fn iterators() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator_map`
[INFO] [stderr]    --> src/main.rs:226:1
[INFO] [stderr]     |
[INFO] [stderr] 226 | fn iterator_map() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator_sum`
[INFO] [stderr]    --> src/main.rs:232:1
[INFO] [stderr]     |
[INFO] [stderr] 232 | fn iterator_sum() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `news_aggregate`
[INFO] [stderr]    --> src/main.rs:269:1
[INFO] [stderr]     |
[INFO] [stderr] 269 | fn news_aggregate() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `vector`
[INFO] [stderr]    --> src/main.rs:305:1
[INFO] [stderr]     |
[INFO] [stderr] 305 | fn vector() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Counter`
[INFO] [stderr]    --> src/main.rs:325:1
[INFO] [stderr]     |
[INFO] [stderr] 325 | struct Counter {
[INFO] [stderr]     | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]    --> src/main.rs:330:5
[INFO] [stderr]     |
[INFO] [stderr] 330 |     fn new() -> Counter {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `if_let`
[INFO] [stderr]    --> src/main.rs:351:1
[INFO] [stderr]     |
[INFO] [stderr] 351 | fn if_let() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `value_in_cents`
[INFO] [stderr]    --> src/main.rs:359:1
[INFO] [stderr]     |
[INFO] [stderr] 359 | fn value_in_cents(coin : Coin) -> u32 {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `option`
[INFO] [stderr]    --> src/main.rs:371:1
[INFO] [stderr]     |
[INFO] [stderr] 371 | fn option() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `messages`
[INFO] [stderr]    --> src/main.rs:378:1
[INFO] [stderr]     |
[INFO] [stderr] 378 | fn messages() {
[INFO] [stderr]     | ^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `rectangles`
[INFO] [stderr]    --> src/main.rs:383:1
[INFO] [stderr]     |
[INFO] [stderr] 383 | fn rectangles() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/main.rs:395:1
[INFO] [stderr]     |
[INFO] [stderr] 395 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `coins`
[INFO] [stderr]    --> src/main.rs:404:1
[INFO] [stderr]     |
[INFO] [stderr] 404 | fn coins() {
[INFO] [stderr]     | ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `slices`
[INFO] [stderr]    --> src/main.rs:409:1
[INFO] [stderr]     |
[INFO] [stderr] 409 | fn slices() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_ownership`
[INFO] [stderr]    --> src/main.rs:419:1
[INFO] [stderr]     |
[INFO] [stderr] 419 | fn takes_ownership(some_string: String) {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `makes_copy`
[INFO] [stderr]    --> src/main.rs:423:1
[INFO] [stderr]     |
[INFO] [stderr] 423 | fn makes_copy(some_integer: i32) {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `first_word`
[INFO] [stderr]    --> src/main.rs:427:1
[INFO] [stderr]     |
[INFO] [stderr] 427 | fn first_word(s: &String) -> usize {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `guess_number`
[INFO] [stderr]    --> src/main.rs:440:1
[INFO] [stderr]     |
[INFO] [stderr] 440 | fn guess_number() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:245:5
[INFO] [stderr]     |
[INFO] [stderr] 245 |     read_username_from_file();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_must_use)] on by default
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `num`
[INFO] [stderr]    --> src/main.rs:177:45
[INFO] [stderr]     |
[INFO] [stderr] 177 |     let mut expensive_result = Cacher::new(|num| {
[INFO] [stderr]     |                                             ^^^ help: consider prefixing with an underscore: `_num`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `equal_to_x`
[INFO] [stderr]    --> src/main.rs:212:9
[INFO] [stderr]     |
[INFO] [stderr] 212 |     let equal_to_x = |z : u32| z == x;
[INFO] [stderr]     |         ^^^^^^^^^^ help: consider prefixing with an underscore: `_equal_to_x`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]    --> src/main.rs:213:9
[INFO] [stderr]     |
[INFO] [stderr] 213 |     let y = 4;
[INFO] [stderr]     |         ^ help: consider prefixing with an underscore: `_y`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `res`
[INFO] [stderr]    --> src/main.rs:229:9
[INFO] [stderr]     |
[INFO] [stderr] 229 |     let res: Vec<_> = v1.iter().map(|x| x + 1).collect();
[INFO] [stderr]     |         ^^^ help: consider prefixing with an underscore: `_res`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `total`
[INFO] [stderr]    --> src/main.rs:236:9
[INFO] [stderr]     |
[INFO] [stderr] 236 |     let total: i32 = v1_iter.sum();
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_total`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `item`
[INFO] [stderr]    --> src/main.rs:289:9
[INFO] [stderr]     |
[INFO] [stderr] 289 |     let item = map.get(&key).unwrap();
[INFO] [stderr]     |         ^^^^ help: consider prefixing with an underscore: `_item`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s3`
[INFO] [stderr]    --> src/main.rs:296:9
[INFO] [stderr]     |
[INFO] [stderr] 296 |     let s3 = s1 + &s2;
[INFO] [stderr]     |         ^^ help: consider prefixing with an underscore: `_s3`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `v`
[INFO] [stderr]    --> src/main.rs:306:9
[INFO] [stderr]     |
[INFO] [stderr] 306 |     let v: Vec<i32> = Vec::new();
[INFO] [stderr]     |         ^ help: consider prefixing with an underscore: `_v`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `third`
[INFO] [stderr]    --> src/main.rs:309:9
[INFO] [stderr]     |
[INFO] [stderr] 309 |     let third: &i32 = &v[2];
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_third`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_number`
[INFO] [stderr]    --> src/main.rs:372:9
[INFO] [stderr]     |
[INFO] [stderr] 372 |     let some_number = Some(5);
[INFO] [stderr]     |         ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_number`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `some_string`
[INFO] [stderr]    --> src/main.rs:373:9
[INFO] [stderr]     |
[INFO] [stderr] 373 |     let some_string = Some("A string");
[INFO] [stderr]     |         ^^^^^^^^^^^ help: consider prefixing with an underscore: `_some_string`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `absent_number`
[INFO] [stderr]    --> src/main.rs:375:9
[INFO] [stderr]     |
[INFO] [stderr] 375 |     let absent_number : Option<i32> = None;
[INFO] [stderr]     |         ^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_absent_number`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `rect3`
[INFO] [stderr]    --> src/main.rs:387:9
[INFO] [stderr]     |
[INFO] [stderr] 387 |     let rect3 = Rectangle {width: 60, height: 45};
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_rect3`
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `NewsArticle`
[INFO] [stderr]  --> src/news_aggregator/mod.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     pub struct NewsArticle {
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Tweet`
[INFO] [stderr]   --> src/news_aggregator/mod.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     pub struct Tweet {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Pair`
[INFO] [stderr]   --> src/main.rs:18:1
[INFO] [stderr]    |
[INFO] [stderr] 18 | struct Pair<T> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/main.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     fn new(x: T, y: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `cmp_display`
[INFO] [stderr]   --> src/main.rs:33:5
[INFO] [stderr]    |
[INFO] [stderr] 33 |     fn cmp_display(&self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `User`
[INFO] [stderr]   --> src/main.rs:42:1
[INFO] [stderr]    |
[INFO] [stderr] 42 | struct User {
[INFO] [stderr]    | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Rectangle`
[INFO] [stderr]   --> src/main.rs:49:1
[INFO] [stderr]    |
[INFO] [stderr] 49 | struct Rectangle {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `area`
[INFO] [stderr]   --> src/main.rs:55:5
[INFO] [stderr]    |
[INFO] [stderr] 55 |     fn area(&self) -> u32 {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `can_hold`
[INFO] [stderr]   --> src/main.rs:59:5
[INFO] [stderr]    |
[INFO] [stderr] 59 |     fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `square`
[INFO] [stderr]   --> src/main.rs:63:5
[INFO] [stderr]    |
[INFO] [stderr] 63 |     fn square(size: u32) -> Rectangle {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `IpAddrKind`
[INFO] [stderr]   --> src/main.rs:68:1
[INFO] [stderr]    |
[INFO] [stderr] 68 | enum IpAddrKind {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `UsState`
[INFO] [stderr]   --> src/main.rs:74:1
[INFO] [stderr]    |
[INFO] [stderr] 74 | enum UsState {
[INFO] [stderr]    | ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Coin`
[INFO] [stderr]   --> src/main.rs:80:1
[INFO] [stderr]    |
[INFO] [stderr] 80 | enum Coin {
[INFO] [stderr]    | ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Message`
[INFO] [stderr]   --> src/main.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | enum Message {
[INFO] [stderr]    | ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `call`
[INFO] [stderr]   --> src/main.rs:95:5
[INFO] [stderr]    |
[INFO] [stderr] 95 |     fn call(&self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `largest`
[INFO] [stderr]    --> src/main.rs:100:2
[INFO] [stderr]     |
[INFO] [stderr] 100 |  fn largest<T : PartialOrd>(list: &[T]) -> &T {
[INFO] [stderr]     |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Point`
[INFO] [stderr]    --> src/main.rs:112:1
[INFO] [stderr]     |
[INFO] [stderr] 112 | struct Point<T> {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `simulated_expensive_calculation`
[INFO] [stderr]    --> src/main.rs:204:1
[INFO] [stderr]     |
[INFO] [stderr] 204 | fn simulated_expensive_calculation(intensity: u32) -> u32 {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `closure_capturing_context`
[INFO] [stderr]    --> src/main.rs:210:1
[INFO] [stderr]     |
[INFO] [stderr] 210 | fn closure_capturing_context() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterators`
[INFO] [stderr]    --> src/main.rs:217:1
[INFO] [stderr]     |
[INFO] [stderr] 217 | fn iterators() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator_map`
[INFO] [stderr]    --> src/main.rs:226:1
[INFO] [stderr]     |
[INFO] [stderr] 226 | fn iterator_map() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator_sum`
[INFO] [stderr]    --> src/main.rs:232:1
[INFO] [stderr]     |
[INFO] [stderr] 232 | fn iterator_sum() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `news_aggregate`
[INFO] [stderr]    --> src/main.rs:269:1
[INFO] [stderr]     |
[INFO] [stderr] 269 | fn news_aggregate() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `vector`
[INFO] [stderr]    --> src/main.rs:305:1
[INFO] [stderr]     |
[INFO] [stderr] 305 | fn vector() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Counter`
[INFO] [stderr]    --> src/main.rs:325:1
[INFO] [stderr]     |
[INFO] [stderr] 325 | struct Counter {
[INFO] [stderr]     | ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]    --> src/main.rs:330:5
[INFO] [stderr]     |
[INFO] [stderr] 330 |     fn new() -> Counter {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `if_let`
[INFO] [stderr]    --> src/main.rs:351:1
[INFO] [stderr]     |
[INFO] [stderr] 351 | fn if_let() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `value_in_cents`
[INFO] [stderr]    --> src/main.rs:359:1
[INFO] [stderr]     |
[INFO] [stderr] 359 | fn value_in_cents(coin : Coin) -> u32 {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `option`
[INFO] [stderr]    --> src/main.rs:371:1
[INFO] [stderr]     |
[INFO] [stderr] 371 | fn option() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `messages`
[INFO] [stderr]    --> src/main.rs:378:1
[INFO] [stderr]     |
[INFO] [stderr] 378 | fn messages() {
[INFO] [stderr]     | ^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `rectangles`
[INFO] [stderr]    --> src/main.rs:383:1
[INFO] [stderr]     |
[INFO] [stderr] 383 | fn rectangles() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `build_user`
[INFO] [stderr]    --> src/main.rs:395:1
[INFO] [stderr]     |
[INFO] [stderr] 395 | fn build_user(email: String, username: String) -> User {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `coins`
[INFO] [stderr]    --> src/main.rs:404:1
[INFO] [stderr]     |
[INFO] [stderr] 404 | fn coins() {
[INFO] [stderr]     | ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `slices`
[INFO] [stderr]    --> src/main.rs:409:1
[INFO] [stderr]     |
[INFO] [stderr] 409 | fn slices() {
[INFO] [stderr]     | ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_ownership`
[INFO] [stderr]    --> src/main.rs:419:1
[INFO] [stderr]     |
[INFO] [stderr] 419 | fn takes_ownership(some_string: String) {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `makes_copy`
[INFO] [stderr]    --> src/main.rs:423:1
[INFO] [stderr]     |
[INFO] [stderr] 423 | fn makes_copy(some_integer: i32) {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `first_word`
[INFO] [stderr]    --> src/main.rs:427:1
[INFO] [stderr]     |
[INFO] [stderr] 427 | fn first_word(s: &String) -> usize {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `guess_number`
[INFO] [stderr]    --> src/main.rs:440:1
[INFO] [stderr]     |
[INFO] [stderr] 440 | fn guess_number() {
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:245:5
[INFO] [stderr]     |
[INFO] [stderr] 245 |     read_username_from_file();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_must_use)] on by default
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.70s
[INFO] running `"docker" "inspect" "eca5f8c7e0c7166c4817ff8a2aa12b8ead07f1b104bc53d1c328f34e07f7164b"`
[INFO] running `"docker" "rm" "-f" "eca5f8c7e0c7166c4817ff8a2aa12b8ead07f1b104bc53d1c328f34e07f7164b"`
[INFO] [stdout] eca5f8c7e0c7166c4817ff8a2aa12b8ead07f1b104bc53d1c328f34e07f7164b