[INFO] cloning repository https://github.com/zongzi531/rust-learning
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/zongzi531/rust-learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzongzi531%2Frust-learning", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzongzi531%2Frust-learning'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] dcf7c60aecad6474095e9df0da0409a19ff70b09
[INFO] checking zongzi531/rust-learning against try#149edce6c6ee840adb602803b96d083101ef3592 for pr-133502-16
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzongzi531%2Frust-learning" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/zongzi531/rust-learning
[INFO] finished tweaking git repo https://github.com/zongzi531/rust-learning
[INFO] tweaked toml for git repo https://github.com/zongzi531/rust-learning written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/zongzi531/rust-learning on toolchain 149edce6c6ee840adb602803b96d083101ef3592
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+149edce6c6ee840adb602803b96d083101ef3592" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/zongzi531/rust-learning 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" "+149edce6c6ee840adb602803b96d083101ef3592" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+149edce6c6ee840adb602803b96d083101ef3592" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 51e6f0d5cfb8a684704e667d81b9a1212e932702585b6a6d1ae63499b193660f
[INFO] running `Command { std: "docker" "start" "-a" "51e6f0d5cfb8a684704e667d81b9a1212e932702585b6a6d1ae63499b193660f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "51e6f0d5cfb8a684704e667d81b9a1212e932702585b6a6d1ae63499b193660f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "51e6f0d5cfb8a684704e667d81b9a1212e932702585b6a6d1ae63499b193660f", kill_on_drop: false }`
[INFO] [stdout] 51e6f0d5cfb8a684704e667d81b9a1212e932702585b6a6d1ae63499b193660f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+149edce6c6ee840adb602803b96d083101ef3592" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c1f634b61656b7141f489b47bb6999680e658ff862bfa9898ef6bac3b2b1ae2d
[INFO] running `Command { std: "docker" "start" "-a" "c1f634b61656b7141f489b47bb6999680e658ff862bfa9898ef6bac3b2b1ae2d", kill_on_drop: false }`
[INFO] [stderr]     Checking utf8_slice v1.0.0
[INFO] [stderr]     Checking rust-learning v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function `get_option` is never used
[INFO] [stdout]  --> src/bin/basic-types-functions-4.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn get_option(tp: u8) -> Option<i32> {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `never_return_fn` is never used
[INFO] [stdout]   --> src/bin/basic-types-functions-4.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn never_return_fn() -> ! {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/bin/lifetime-basic-5.rs:11:7
[INFO] [stdout]    |
[INFO] [stdout] 11 |   let y: & i32 = &_x;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/bin/generics-traits-traits-8.rs:8:6
[INFO] [stdout]   |
[INFO] [stdout] 7 | impl<T> Pair<T> {
[INFO] [stdout]   | --------------- associated function in this implementation
[INFO] [stdout] 8 |   fn new(x: T, y: T) -> Self {
[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: `name`
[INFO] [stdout]  --> src/bin/flow-control-4.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   for name in &names {
[INFO] [stdout]   |       ^^^^ help: if this is intentional, prefix it with an underscore: `_name`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `n`
[INFO] [stdout]   --> src/bin/flow-control-4.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   for n in numbers {
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_n`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]  --> src/bin/compound-types-string-1.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let s: &str = "hello, world";
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arrays`
[INFO] [stdout]  --> src/bin/generics-traits-const-generics-1.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 |   let arrays = [
[INFO] [stdout]   |       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_arrays`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `data` is never read
[INFO] [stdout]  --> src/bin/generics-traits-const-generics-1.rs:4:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Array<T, const N: usize> {
[INFO] [stdout]   |        ----- field in this struct
[INFO] [stdout] 4 |   data : [T; N]
[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: `v`
[INFO] [stdout]   --> src/bin/collections-vector-1.rs:28:11
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn is_vec(v: &Vec<u8>) {}
[INFO] [stdout]    |           ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: irrefutable `if let` pattern
[INFO] [stdout]  --> src/bin/compound-types-enum-5.rs:8:6
[INFO] [stdout]   |
[INFO] [stdout] 8 |   if let n = six {
[INFO] [stdout]   |      ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this pattern will always match, so the `if let` is useless
[INFO] [stdout]   = help: consider replacing the `if let` with a `let`
[INFO] [stdout]   = note: `#[warn(irrefutable_let_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]  --> src/bin/compound-types-enum-5.rs:6:7
[INFO] [stdout]   |
[INFO] [stdout] 6 |   let none = plus_one(None);
[INFO] [stdout]   |       ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: if this is intentional, prefix it with an underscore
[INFO] [stdout]   |
[INFO] [stdout] 6 |   let _none = plus_one(None);
[INFO] [stdout]   |       +
[INFO] [stdout] help: you might have meant to pattern match on the similarly named variant `None`
[INFO] [stdout]   |
[INFO] [stdout] 6 -   let none = plus_one(None);
[INFO] [stdout] 6 +   let std::prelude::v1::None = plus_one(None);
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: irrefutable `if let` pattern
[INFO] [stdout]   --> src/bin/pattern-match-match-iflet-7.rs:10:6
[INFO] [stdout]    |
[INFO] [stdout] 10 |   if let Foo::Bar(i) = a {
[INFO] [stdout]    |      ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this pattern will always match, so the `if let` is useless
[INFO] [stdout]    = help: consider replacing the `if let` with a `let`
[INFO] [stdout]    = note: `#[warn(irrefutable_let_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width` and `height` are never read
[INFO] [stdout]  --> src/bin/compound-types-struct-7.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Rectangle {
[INFO] [stdout]   |        --------- fields in this struct
[INFO] [stdout] 5 |     width: u32,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout] 6 |     height: u32,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `Rectangle` 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: unused variable: `s`
[INFO] [stdout]  --> src/bin/ownership-borrowing-8.rs:9:18
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn borrow_object(s: &mut String) {}
[INFO] [stdout]   |                  ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arr0`
[INFO] [stdout]  --> src/bin/compound-types-array-2.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let arr0 = [1, 2, 3];
[INFO] [stdout]   |       ^^^^ help: if this is intentional, prefix it with an underscore: `_arr0`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]   --> src/bin/compound-types-struct-2.rs:16:27
[INFO] [stdout]    |
[INFO] [stdout] 16 | fn do_something_with_unit(u: Unit) {   }
[INFO] [stdout]    |                           ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `SomeTrait` is never used
[INFO] [stdout]  --> src/bin/compound-types-struct-2.rs:3:7
[INFO] [stdout]   |
[INFO] [stdout] 3 | trait SomeTrait {
[INFO] [stdout]   |       ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/bin/compound-types-array-4.rs:3:12
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct I64(i64);
[INFO] [stdout]   |        --- ^^^
[INFO] [stdout]   |        |
[INFO] [stdout]   |        field in this struct
[INFO] [stdout]   |
[INFO] [stdout]   = help: consider removing this field
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/bin/compound-types-array-4.rs:4:13
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Char(char);
[INFO] [stdout]   |        ---- ^^^^
[INFO] [stdout]   |        |
[INFO] [stdout]   |        field in this struct
[INFO] [stdout]   |
[INFO] [stdout]   = help: consider removing this field
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/bin/compound-types-array-4.rs:10:7
[INFO] [stdout]    |
[INFO] [stdout] 10 |   I64(i64),
[INFO] [stdout]    |   --- ^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 10 -   I64(i64),
[INFO] [stdout] 10 +   I64(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/bin/compound-types-array-4.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout] 11 |   Char(char),
[INFO] [stdout]    |   ---- ^^^^
[INFO] [stdout]    |   |
[INFO] [stdout]    |   field in this variant
[INFO] [stdout]    |
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 11 -   Char(char),
[INFO] [stdout] 11 +   Char(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/bin/pattern-match-match-iflet-8.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   Qux(u32)
[INFO] [stdout]   |   --- ^^^
[INFO] [stdout]   |   |
[INFO] [stdout]   |   field in this variant
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 5 -   Qux(u32)
[INFO] [stdout] 5 +   Qux(())
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Bar` and `Baz` are never constructed
[INFO] [stdout]  --> src/bin/pattern-match-match-iflet-8.rs:3:3
[INFO] [stdout]   |
[INFO] [stdout] 2 | enum Foo {
[INFO] [stdout]   |      --- variants in this enum
[INFO] [stdout] 3 |   Bar,
[INFO] [stdout]   |   ^^^
[INFO] [stdout] 4 |   Baz,
[INFO] [stdout]   |   ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `y` is never read
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:3:3
[INFO] [stdout]   |
[INFO] [stdout] 3 |   y = x;                      
[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: `r`
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let r: &'b &'a i32 = &&0;   
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_r`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `y` is assigned to, but never used
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:2:34
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn f<'a: 'b, 'b>(x: &'a i32, mut y: &'b i32) {
[INFO] [stdout]   |                                  ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_y` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `y` is never read
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:8:3
[INFO] [stdout]   |
[INFO] [stdout] 8 |   y = x;                      // &'a i32 is a subtype of &'b i32 because 'a: 'b
[INFO] [stdout]   |   ^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r`
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let r: &'b &'a i32 = &&0;   // &'b &'a i32 is well formed because 'a: 'b
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_r`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `y` is assigned to, but never used
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:7:31
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn f2<'a, 'b>(x: &'a i32, mut y: &'b i32) where 'a: 'b {
[INFO] [stdout]   |                               ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_y` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `f` is never used
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn f<'a: 'b, 'b>(x: &'a i32, mut y: &'b i32) {
[INFO] [stdout]   |    ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `f2` is never used
[INFO] [stdout]  --> src/bin/lifetime-advance-3.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn f2<'a, 'b>(x: &'a i32, mut y: &'b i32) where 'a: 'b {
[INFO] [stdout]   |    ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `invalid_output` is never used
[INFO] [stdout]   --> src/bin/lifetime-basic-4.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn invalid_output<'a>(s: &'a String) -> &'a String { 
[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 `ImportantExcerpt` is never constructed
[INFO] [stdout]  --> src/bin/lifetime-basic-9.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct ImportantExcerpt<'a> {
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `level` is never used
[INFO] [stdout]  --> src/bin/lifetime-basic-9.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 6 | impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]   | ----------------------------- method in this implementation
[INFO] [stdout] 7 |   fn level(&'a self) -> i32 {
[INFO] [stdout]   |      ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]   --> src/bin/generics-traits-generics-4.rs:10:7
[INFO] [stdout]    |
[INFO] [stdout] 10 |   let p = Point{x: 5, y : "hello".to_string()};
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `x` and `y` are never read
[INFO] [stdout]  --> src/bin/generics-traits-generics-4.rs:4:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Point<T, U> {
[INFO] [stdout]   |        ----- fields in this struct
[INFO] [stdout] 4 |   x: T,
[INFO] [stdout]   |   ^
[INFO] [stdout] 5 |   y: U,
[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: `s1`
[INFO] [stdout]  --> src/bin/compound-types-slice-1.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   let s1: &[i32] = &arr[0..2];
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]  --> src/bin/compound-types-slice-1.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |   let s2: &str = "hello, world" as &str;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/bin/type-conversions-as-2.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 |   let v = 1000 as u8;
[INFO] [stdout]   |       ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]   --> src/bin/compound-types-struct-1.rs:10:7
[INFO] [stdout]    |
[INFO] [stdout] 10 |   let p = Person {
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name`, `age`, and `hobby` are never read
[INFO] [stdout]  --> src/bin/compound-types-struct-1.rs:4:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Person {
[INFO] [stdout]   |        ------ fields in this struct
[INFO] [stdout] 4 |   name: String,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout] 5 |   age: u8,
[INFO] [stdout]   |   ^^^
[INFO] [stdout] 6 |   hobby: String
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `fly` is never used
[INFO] [stdout]   --> src/bin/generics-traits-trait-object-1.rs:14:6
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl Swan {
[INFO] [stdout]    | --------- method in this implementation
[INFO] [stdout] 14 |   fn fly(&self) {
[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 `a` and `b` are never read
[INFO] [stdout]  --> src/bin/lifetime-basic-7.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | struct Example<'a, 'b> {
[INFO] [stdout]   |        ------- fields in this struct
[INFO] [stdout] 8 |     a: &'a u32,
[INFO] [stdout]   |     ^
[INFO] [stdout] 9 |     b: &'b NoCopyType
[INFO] [stdout]   |     ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `Example` 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: unused variable: `v`
[INFO] [stdout]   --> src/bin/collections-vector-1.rs:28:11
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn is_vec(v: &Vec<u8>) {}
[INFO] [stdout]    |           ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `get_option` is never used
[INFO] [stdout]  --> src/bin/basic-types-functions-4.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn get_option(tp: u8) -> Option<i32> {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `never_return_fn` is never used
[INFO] [stdout]   --> src/bin/basic-types-functions-4.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn never_return_fn() -> ! {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/ownership-borrowing-3.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let mut s = String::from("hello, ");
[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: unused variable: `s`
[INFO] [stdout]  --> src/bin/ownership-borrowing-3.rs:9:18
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn borrow_object(s: &String) {}
[INFO] [stdout]   |                  ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `ImportantExcerpt` is never constructed
[INFO] [stdout]  --> src/bin/lifetime-advance-2.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct ImportantExcerpt<'a> {
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `announce_and_return_part` is never used
[INFO] [stdout]  --> src/bin/lifetime-advance-2.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 6 | impl<'a: 'b, 'b> ImportantExcerpt<'a> {
[INFO] [stdout]   | ------------------------------------- method in this implementation
[INFO] [stdout] 7 |   fn announce_and_return_part(&'a self, announcement: &'b str) -> &'b str {
[INFO] [stdout]   |      ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `DoubleRef` is never constructed
[INFO] [stdout]  --> src/bin/lifetime-advance-1.rs:5:8
[INFO] [stdout]   |
[INFO] [stdout] 5 | struct DoubleRef<'a, 'b: 'a,  T> {
[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: `u2`
[INFO] [stdout]   --> src/bin/compound-types-struct-6.rs:17:7
[INFO] [stdout]    |
[INFO] [stdout] 17 |   let u2 = set_email(u1);
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_u2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `active`, `username`, `email`, and `sign_in_count` are never read
[INFO] [stdout]  --> src/bin/compound-types-struct-6.rs:4:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct User {
[INFO] [stdout]   |        ---- fields in this struct
[INFO] [stdout] 4 |   active: bool,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout] 5 |   username: String,
[INFO] [stdout]   |   ^^^^^^^^
[INFO] [stdout] 6 |   email: String,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 7 |   sign_in_count: u64,
[INFO] [stdout]   |   ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (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/ownership-borrowing-7.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   let mut s = String::from("hello");
[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: unused variable: `y`
[INFO] [stdout]   --> src/bin/lifetime-basic-5.rs:11:7
[INFO] [stdout]    |
[INFO] [stdout] 11 |   let y: & i32 = &_x;
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]  --> src/bin/ownership-borrowing-11.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   let r1 = &mut s;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]  --> src/bin/ownership-borrowing-11.rs:6:7
[INFO] [stdout]   |
[INFO] [stdout] 6 |   let r2 = &mut s;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c1`
[INFO] [stdout]  --> src/bin/type-conversions-as-1.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 |   let c1: char = decimal as u8 as char;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_c1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c2`
[INFO] [stdout]  --> src/bin/type-conversions-as-1.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let c2 = integer as char;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_c2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ele`
[INFO] [stdout]  --> src/bin/result-panic-panic-2.rs:6:7
[INFO] [stdout]   |
[INFO] [stdout] 6 |   let ele = v[2];
[INFO] [stdout]   |       ^^^ help: if this is intentional, prefix it with an underscore: `_ele`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `East`, `West`, and `North` are never constructed
[INFO] [stdout]  --> src/bin/pattern-match-match-iflet-1.rs:4:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | enum Direction {
[INFO] [stdout]   |      --------- variants in this enum
[INFO] [stdout] 4 |   East,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout] 5 |   West,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout] 6 |   North,
[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: `ele`
[INFO] [stdout]  --> src/bin/result-panic-panic-2.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |   let ele = v.get(2).unwrap();
[INFO] [stdout]   |       ^^^ help: if this is intentional, prefix it with an underscore: `_ele`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/bin/result-panic-panic-2.rs:10:7
[INFO] [stdout]    |
[INFO] [stdout] 10 |   let v = production_rate_per_hour(2);
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]  --> src/bin/compound-types-tuple-5.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 |   let (x, y, z): (i32, i32, i32);
[INFO] [stdout]   |        ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]  --> src/bin/compound-types-tuple-5.rs:2:11
[INFO] [stdout]   |
[INFO] [stdout] 2 |   let (x, y, z): (i32, i32, i32);
[INFO] [stdout]   |           ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]  --> src/bin/compound-types-tuple-5.rs:2:14
[INFO] [stdout]   |
[INFO] [stdout] 2 |   let (x, y, z): (i32, i32, i32);
[INFO] [stdout]   |              ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c1`
[INFO] [stdout]  --> src/bin/type-conversions-as-1.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 |   let c1: char = decimal as u8 as char;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_c1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c2`
[INFO] [stdout]  --> src/bin/type-conversions-as-1.rs:9:7
[INFO] [stdout]   |
[INFO] [stdout] 9 |   let c2 = integer as char;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_c2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Color` is never constructed
[INFO] [stdout]  --> src/bin/compound-types-struct-3.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Color(i32, i32, i32);
[INFO] [stdout]   |        ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: irrefutable `if let` pattern
[INFO] [stdout]   --> src/bin/pattern-match-match-iflet-7.rs:10:6
[INFO] [stdout]    |
[INFO] [stdout] 10 |   if let Foo::Bar(i) = a {
[INFO] [stdout]    |      ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this pattern will always match, so the `if let` is useless
[INFO] [stdout]    = help: consider replacing the `if let` with a `let`
[INFO] [stdout]    = note: `#[warn(irrefutable_let_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Person` is never constructed
[INFO] [stdout]  --> src/bin/compound-types-struct-5.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Person {
[INFO] [stdout]   |        ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `build_person` is never used
[INFO] [stdout]  --> src/bin/compound-types-struct-5.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn build_person(name: String, age: u8) -> Person {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]  --> src/bin/compound-types-string-8.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   let s1: &str = &s;
[INFO] [stdout]   |       ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `ImportantExcerpt` is never constructed
[INFO] [stdout]  --> src/bin/lifetime-basic-9.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct ImportantExcerpt<'a> {
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `level` is never used
[INFO] [stdout]  --> src/bin/lifetime-basic-9.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 6 | impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]   | ----------------------------- method in this implementation
[INFO] [stdout] 7 |   fn level(&'a self) -> i32 {
[INFO] [stdout]   |      ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `width` and `height` are never read
[INFO] [stdout]  --> src/bin/compound-types-struct-7.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Rectangle {
[INFO] [stdout]   |        --------- fields in this struct
[INFO] [stdout] 5 |     width: u32,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout] 6 |     height: u32,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `Rectangle` 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: function `longest` is never used
[INFO] [stdout]  --> src/bin/lifetime-basic-3.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0001]: `-Znext-solver=globally` and `generic_const_exprs` are incompatible, using them at the same time is not allowed
[INFO] [stdout]  --> src/bin/generics-traits-const-generics-3.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(generic_const_exprs)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: remove one of these features
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0001`.
[INFO] [stdout] 
[INFO] [stdout] warning: calls to `std::str::from_utf8` with an invalid literal always return an error
[INFO] [stdout]   --> src/bin/compound-types-string-10-1.rs:34:11
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let shift_jis = b"\x82\xe6\x82\xa8\x82\xb1\x82\xbb"; // "ようこそ" in SHIFT-JIS
[INFO] [stdout]    |                     ----------------------------------- the literal was valid UTF-8 up to the 0 bytes
[INFO] [stdout] ...
[INFO] [stdout] 34 |     match str::from_utf8(shift_jis) {
[INFO] [stdout]    |           ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(invalid_from_utf8)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust-learning` (bin "generics-traits-const-generics-3") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `arr0`
[INFO] [stdout]  --> src/bin/compound-types-array-2.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 |   let arr0 = [1, 2, 3];
[INFO] [stdout]   |       ^^^^ help: if this is intentional, prefix it with an underscore: `_arr0`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]  --> src/bin/method-5.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct Rectangle {
[INFO] [stdout]   |        ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `area` is never used
[INFO] [stdout]  --> src/bin/method-5.rs:9:6
[INFO] [stdout]   |
[INFO] [stdout] 8 | impl Rectangle {
[INFO] [stdout]   | -------------- method in this implementation
[INFO] [stdout] 9 |   fn area(&self) -> u32 {
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `can_hold` is never used
[INFO] [stdout]   --> src/bin/method-5.rs:15:6
[INFO] [stdout]    |
[INFO] [stdout] 14 | impl Rectangle {
[INFO] [stdout]    | -------------- method in this implementation
[INFO] [stdout] 15 |   fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |      ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/bin/ownership-borrowing-9.rs:11:18
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn borrow_object(s: &String) {}
[INFO] [stdout]    |                  ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `name`
[INFO] [stdout]  --> src/bin/flow-control-4.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 |   for name in &names {
[INFO] [stdout]   |       ^^^^ help: if this is intentional, prefix it with an underscore: `_name`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `n`
[INFO] [stdout]   --> src/bin/flow-control-4.rs:13:7
[INFO] [stdout]    |
[INFO] [stdout] 13 |   for n in numbers {
[INFO] [stdout]    |       ^ help: if this is intentional, prefix it with an underscore: `_n`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "c1f634b61656b7141f489b47bb6999680e658ff862bfa9898ef6bac3b2b1ae2d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c1f634b61656b7141f489b47bb6999680e658ff862bfa9898ef6bac3b2b1ae2d", kill_on_drop: false }`
[INFO] [stdout] c1f634b61656b7141f489b47bb6999680e658ff862bfa9898ef6bac3b2b1ae2d