[INFO] cloning repository https://github.com/bookinstock/rust_example
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/bookinstock/rust_example" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbookinstock%2Frust_example", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbookinstock%2Frust_example'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c83d144f2d500cd60a59da5019b4bc5ca7d2d36f
[INFO] checking bookinstock/rust_example against try#3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbookinstock%2Frust_example" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/bookinstock/rust_example on toolchain 3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/bookinstock/rust_example
[INFO] finished tweaking git repo https://github.com/bookinstock/rust_example
[INFO] tweaked toml for git repo https://github.com/bookinstock/rust_example written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/bookinstock/rust_example already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f86c13c0fa4adcd69f468148da2c549f48b42f6aac212fd87a0262d6c18efc9c
[INFO] running `Command { std: "docker" "start" "-a" "f86c13c0fa4adcd69f468148da2c549f48b42f6aac212fd87a0262d6c18efc9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f86c13c0fa4adcd69f468148da2c549f48b42f6aac212fd87a0262d6c18efc9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f86c13c0fa4adcd69f468148da2c549f48b42f6aac212fd87a0262d6c18efc9c", kill_on_drop: false }`
[INFO] [stdout] f86c13c0fa4adcd69f468148da2c549f48b42f6aac212fd87a0262d6c18efc9c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 66c5fbec52b9f7b40155eeb4e366f2c5ebaffe3b4ace10b0979bb7d4d4a42f29
[INFO] running `Command { std: "docker" "start" "-a" "66c5fbec52b9f7b40155eeb4e366f2c5ebaffe3b4ace10b0979bb7d4d4a42f29", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_example v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `From` is imported redundantly
[INFO] [stdout]    --> src/bin/conversion.rs:53:9
[INFO] [stdout]     |
[INFO] [stdout] 53  |     use std::convert::From;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `ToString` is imported redundantly
[INFO] [stdout]    --> src/bin/conversion.rs:106:9
[INFO] [stdout]     |
[INFO] [stdout] 106 |     use std::string::ToString;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_string`
[INFO] [stdout]   --> src/bin/conversion.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let my_string = String::from(my_str);
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_string`
[INFO] [stdout]    |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]   --> src/bin/conversion.rs:45:8
[INFO] [stdout]    |
[INFO] [stdout] 45 | #[warn(unused_variables)]
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/bin/scope.rs:88:9
[INFO] [stdout]    |
[INFO] [stdout] 88 |     let x = ToDrop;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ref_x`
[INFO] [stdout]    --> src/bin/scope.rs:401:13
[INFO] [stdout]     |
[INFO] [stdout] 401 |         let ref_x = &x;
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_ref_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/bin/scope.rs:405:13
[INFO] [stdout]     |
[INFO] [stdout] 405 |         let mut ref_x = &mut x;
[INFO] [stdout]     |             ----^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `futures`
[INFO] [stdout]   --> src/bin/async.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use futures::executor::block_on;
[INFO] [stdout]    |     ^^^^^^^ use of undeclared crate or module `futures`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `ps_ref`
[INFO] [stdout]    --> src/bin/scope.rs:444:4
[INFO] [stdout]     |
[INFO] [stdout] 444 | fn ps_ref() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Nil`
[INFO] [stdout]   --> src/bin/custom_type.rs:30:8
[INFO] [stdout]    |
[INFO] [stdout] 30 | struct Nil;
[INFO] [stdout]    |        ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `block_on` in this scope
[INFO] [stdout]   --> src/bin/async.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     block_on(future); // `future` is run and "hello, world!" is printed
[INFO] [stdout]    |     ^^^^^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `trait`
[INFO] [stdout]   --> src/bin/trait.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | */
[INFO] [stdout]    |    ^ consider adding a `main` function to `src/bin/trait.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_example` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/bin/control_flow.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |         'inner: loop {
[INFO] [stdout]     |         ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: path statement with no effect
[INFO] [stdout]   --> src/bin/expression.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     x;
[INFO] [stdout]    |     ^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(path_statements)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused arithmetic operation that must be used
[INFO] [stdout]   --> src/bin/expression.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     x + 1;
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused arithmetic operation that must be used
[INFO] [stdout]   --> src/bin/expression.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 36 |         2 * x;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `noisy_unused_function`
[INFO] [stdout]   --> src/bin/attribute.rs:33:8
[INFO] [stdout]    |
[INFO] [stdout] 33 |     fn noisy_unused_function() {}
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable statement
[INFO] [stdout]    --> src/bin/control_flow.rs:125:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |             break 'outer;
[INFO] [stdout]     |             ------------ any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 125 |         println!("never reach");
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ unreachable statement
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout]     = note: this warning originates in the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `_m`
[INFO] [stdout]  --> src/bin/_m.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | / pub fn xx() {
[INFO] [stdout] 2 | |     println!("m xx");
[INFO] [stdout] 3 | | }
[INFO] [stdout]   | |_^ consider adding a `main` function to `src/bin/_m.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `error`
[INFO] [stdout]   --> src/bin/error.rs:41:4
[INFO] [stdout]    |
[INFO] [stdout] 41 | */
[INFO] [stdout]    |    ^ consider adding a `main` function to `src/bin/error.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0425, E0433.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0425`.
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/bin/scope.rs:88:9
[INFO] [stdout]    |
[INFO] [stdout] 88 |     let x = ToDrop;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ref_x`
[INFO] [stdout]    --> src/bin/scope.rs:401:13
[INFO] [stdout]     |
[INFO] [stdout] 401 |         let ref_x = &x;
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_ref_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/bin/scope.rs:405:13
[INFO] [stdout]     |
[INFO] [stdout] 405 |         let mut ref_x = &mut x;
[INFO] [stdout]     |             ----^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vec2`
[INFO] [stdout]    --> src/bin/function.rs:391:9
[INFO] [stdout]     |
[INFO] [stdout] 391 |     let vec2 = vec![4, 5, 6];
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_vec2`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `ps_ref`
[INFO] [stdout]    --> src/bin/scope.rs:444:4
[INFO] [stdout]     |
[INFO] [stdout] 444 | fn ps_ref() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `From` is imported redundantly
[INFO] [stdout]    --> src/bin/conversion.rs:53:9
[INFO] [stdout]     |
[INFO] [stdout] 53  |     use std::convert::From;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `ToString` is imported redundantly
[INFO] [stdout]    --> src/bin/conversion.rs:106:9
[INFO] [stdout]     |
[INFO] [stdout] 106 |     use std::string::ToString;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Red`
[INFO] [stdout]    --> src/bin/control_flow.rs:247:9
[INFO] [stdout]     |
[INFO] [stdout] 247 |         Red,
[INFO] [stdout]     |         ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Blue`
[INFO] [stdout]    --> src/bin/control_flow.rs:248:9
[INFO] [stdout]     |
[INFO] [stdout] 248 |         Blue,
[INFO] [stdout]     |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Green`
[INFO] [stdout]    --> src/bin/control_flow.rs:249:9
[INFO] [stdout]     |
[INFO] [stdout] 249 |         Green,
[INFO] [stdout]     |         ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `HSV`
[INFO] [stdout]    --> src/bin/control_flow.rs:251:9
[INFO] [stdout]     |
[INFO] [stdout] 251 |         HSV(u32, u32, u32),
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `HSL`
[INFO] [stdout]    --> src/bin/control_flow.rs:252:9
[INFO] [stdout]     |
[INFO] [stdout] 252 |         HSL(u32, u32, u32),
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `CMY`
[INFO] [stdout]    --> src/bin/control_flow.rs:253:9
[INFO] [stdout]     |
[INFO] [stdout] 253 |         CMY(u32, u32, u32),
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `CMYK`
[INFO] [stdout]    --> src/bin/control_flow.rs:254:9
[INFO] [stdout]     |
[INFO] [stdout] 254 |         CMYK(u32, u32, u32, u32),
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `unsafe`
[INFO] [stdout]  --> src/bin/unsafe.rs:1:2
[INFO] [stdout]   |
[INFO] [stdout] 1 | 
[INFO] [stdout]   |  ^ consider adding a `main` function to `src/bin/unsafe.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `test`
[INFO] [stdout]   --> src/bin/test.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | */
[INFO] [stdout]    |    ^ consider adding a `main` function to `src/bin/test.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: this method call resolves to `<&[T; N] as IntoIterator>::into_iter` (due to backwards compatibility), but will resolve to <[T; N] as IntoIterator>::into_iter in Rust 2021.
[INFO] [stdout]    --> src/bin/function.rs:431:16
[INFO] [stdout]     |
[INFO] [stdout] 431 |         array2.into_iter().find(|&&x| x == 2)
[INFO] [stdout]     |                ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(array_into_iter)]` on by default
[INFO] [stdout]     = warning: this changes meaning in Rust 2021
[INFO] [stdout]     = note: for more information, see issue #66145 <https://github.com/rust-lang/rust/issues/66145>
[INFO] [stdout] help: use `.iter()` instead of `.into_iter()` to avoid ambiguity
[INFO] [stdout]     |
[INFO] [stdout] 431 |         array2.iter().find(|&&x| x == 2)
[INFO] [stdout]     |                ^^^^
[INFO] [stdout] help: or use `IntoIterator::into_iter(..)` instead of `.into_iter()` to explicitly iterate by value
[INFO] [stdout]     |
[INFO] [stdout] 431 |         IntoIterator::into_iter(array2).find(|&&x| x == 2)
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^      ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_string`
[INFO] [stdout]   --> src/bin/conversion.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let my_string = String::from(my_str);
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_string`
[INFO] [stdout]    |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]   --> src/bin/conversion.rs:45:8
[INFO] [stdout]    |
[INFO] [stdout] 45 | #[warn(unused_variables)]
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/bin/control_flow.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |         'inner: loop {
[INFO] [stdout]     |         ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `ttt`
[INFO] [stdout]    --> src/bin/hello.rs:107:4
[INFO] [stdout]     |
[INFO] [stdout] 107 | fn ttt() {
[INFO] [stdout]     |    ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `f`
[INFO] [stdout]    --> src/bin/hello.rs:120:4
[INFO] [stdout]     |
[INFO] [stdout] 120 | fn f() {
[INFO] [stdout]     |    ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test`
[INFO] [stdout]    --> src/bin/hello.rs:124:4
[INFO] [stdout]     |
[INFO] [stdout] 124 | fn test() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `try_debug_trait`
[INFO] [stdout]    --> src/bin/hello.rs:159:4
[INFO] [stdout]     |
[INFO] [stdout] 159 | fn try_debug_trait() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: path statement with no effect
[INFO] [stdout]   --> src/bin/expression.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     x;
[INFO] [stdout]    |     ^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(path_statements)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused arithmetic operation that must be used
[INFO] [stdout]   --> src/bin/expression.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     x + 1;
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused arithmetic operation that must be used
[INFO] [stdout]   --> src/bin/expression.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 36 |         2 * x;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 9 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_literal`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:113:4
[INFO] [stdout]     |
[INFO] [stdout] 113 | fn test_literal() {}
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/bin/generic.rs:217:9
[INFO] [stdout]     |
[INFO] [stdout] 217 |     let s = S(1);
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_array`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn test_array() {}
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_enum`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:117:4
[INFO] [stdout]     |
[INFO] [stdout] 117 | fn test_enum() {}
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_stuct`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:119:4
[INFO] [stdout]     |
[INFO] [stdout] 119 | fn test_stuct() {}
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_variable`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:137:4
[INFO] [stdout]     |
[INFO] [stdout] 137 | fn test_variable() {}
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_wildcard`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:139:4
[INFO] [stdout]     |
[INFO] [stdout] 139 | fn test_wildcard() {}
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_placeholder`
[INFO] [stdout]    --> src/bin/pattern_matching.rs:141:4
[INFO] [stdout]     |
[INFO] [stdout] 141 | fn test_placeholder() {}
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable statement
[INFO] [stdout]    --> src/bin/control_flow.rs:125:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |             break 'outer;
[INFO] [stdout]     |             ------------ any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 125 |         println!("never reach");
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ unreachable statement
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout]     = note: this warning originates in the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Nil`
[INFO] [stdout]   --> src/bin/custom_type.rs:30:8
[INFO] [stdout]    |
[INFO] [stdout] 30 | struct Nil;
[INFO] [stdout]    |        ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vec2`
[INFO] [stdout]    --> src/bin/function.rs:391:9
[INFO] [stdout]     |
[INFO] [stdout] 391 |     let vec2 = vec![4, 5, 6];
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_vec2`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Rich`
[INFO] [stdout]    --> src/bin/custom_type.rs:117:9
[INFO] [stdout]     |
[INFO] [stdout] 117 |         Rich,
[INFO] [stdout]     |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Soldier`
[INFO] [stdout]    --> src/bin/custom_type.rs:123:9
[INFO] [stdout]     |
[INFO] [stdout] 123 |         Soldier,
[INFO] [stdout]     |         ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `logical`
[INFO] [stdout]   --> src/bin/primitive.rs:39:9
[INFO] [stdout]    |
[INFO] [stdout] 39 |     let logical: bool = true;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_logical`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a_float`
[INFO] [stdout]   --> src/bin/primitive.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |     let a_float: f64 = 1.0; // 常规说明
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `an_integer`
[INFO] [stdout]   --> src/bin/primitive.rs:42:9
[INFO] [stdout]    |
[INFO] [stdout] 42 |     let an_integer = 5i32; // 后缀说明
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_an_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_float`
[INFO] [stdout]   --> src/bin/primitive.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let default_float = 3.0; // `f64`
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_integer`
[INFO] [stdout]   --> src/bin/primitive.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let default_integer = 7; // `i32`
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `inferred_type` is assigned to, but never used
[INFO] [stdout]   --> src/bin/primitive.rs:49:13
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let mut inferred_type = 12; // 根据下一行的赋值推断为 i64 类型
[INFO] [stdout]    |             ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_inferred_type` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `inferred_type` is never read
[INFO] [stdout]   --> src/bin/primitive.rs:50:5
[INFO] [stdout]    |
[INFO] [stdout] 50 |     inferred_type = 4294967296i64;
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `mutable` is assigned to, but never used
[INFO] [stdout]   --> src/bin/primitive.rs:53:13
[INFO] [stdout]    |
[INFO] [stdout] 53 |     let mut mutable = 12; // Mutable `i32`
[INFO] [stdout]    |             ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_mutable` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `mutable` is never read
[INFO] [stdout]   --> src/bin/primitive.rs:54:5
[INFO] [stdout]    |
[INFO] [stdout] 54 |     mutable = 21;
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mutable`
[INFO] [stdout]   --> src/bin/primitive.rs:60:9
[INFO] [stdout]    |
[INFO] [stdout] 60 |     let mutable = true;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutable`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this method call resolves to `<&[T; N] as IntoIterator>::into_iter` (due to backwards compatibility), but will resolve to <[T; N] as IntoIterator>::into_iter in Rust 2021.
[INFO] [stdout]    --> src/bin/function.rs:431:16
[INFO] [stdout]     |
[INFO] [stdout] 431 |         array2.into_iter().find(|&&x| x == 2)
[INFO] [stdout]     |                ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(array_into_iter)]` on by default
[INFO] [stdout]     = warning: this changes meaning in Rust 2021
[INFO] [stdout]     = note: for more information, see issue #66145 <https://github.com/rust-lang/rust/issues/66145>
[INFO] [stdout] help: use `.iter()` instead of `.into_iter()` to avoid ambiguity
[INFO] [stdout]     |
[INFO] [stdout] 431 |         array2.iter().find(|&&x| x == 2)
[INFO] [stdout]     |                ^^^^
[INFO] [stdout] help: or use `IntoIterator::into_iter(..)` instead of `.into_iter()` to explicitly iterate by value
[INFO] [stdout]     |
[INFO] [stdout] 431 |         IntoIterator::into_iter(array2).find(|&&x| x == 2)
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^      ^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `S`
[INFO] [stdout]    --> src/bin/generic.rs:135:12
[INFO] [stdout]     |
[INFO] [stdout] 135 |     struct S; // 具体类型 `S`
[INFO] [stdout]     |            ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `GenericVal`
[INFO] [stdout]    --> src/bin/generic.rs:136:12
[INFO] [stdout]     |
[INFO] [stdout] 136 |     struct GenericVal<T>(T); // 泛型类型 `GenericVal`
[INFO] [stdout]     |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `printer`
[INFO] [stdout]    --> src/bin/generic.rs:210:8
[INFO] [stdout]     |
[INFO] [stdout] 210 |     fn printer<T: Display>(t: T) {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "66c5fbec52b9f7b40155eeb4e366f2c5ebaffe3b4ace10b0979bb7d4d4a42f29", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "66c5fbec52b9f7b40155eeb4e366f2c5ebaffe3b4ace10b0979bb7d4d4a42f29", kill_on_drop: false }`
[INFO] [stdout] 66c5fbec52b9f7b40155eeb4e366f2c5ebaffe3b4ace10b0979bb7d4d4a42f29