[INFO] cloning repository https://github.com/kyyril/rust-essentials
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kyyril/rust-essentials" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkyyril%2Frust-essentials", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkyyril%2Frust-essentials'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c6b50017705da774cd0f7384c84ea009868c41eb
[INFO] fixing kyyril/rust-essentials against try#622891a4e29178280638a6b63a8908bde2c0c854+cargoflags=-Zfix-edition=start=2015 for pr-157817-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkyyril%2Frust-essentials" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/kyyril/rust-essentials
[INFO] finished tweaking git repo https://github.com/kyyril/rust-essentials
[INFO] tweaked toml for git repo https://github.com/kyyril/rust-essentials written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/kyyril/rust-essentials on toolchain 622891a4e29178280638a6b63a8908bde2c0c854
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/kyyril/rust-essentials 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" "+622891a4e29178280638a6b63a8908bde2c0c854" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83
[INFO] running `Command { std: "docker" "start" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=" "-e" "RUSTDOCFLAGS=" "-w" "/opt/rustwide/workdir" "--user" "0:0" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "fix" "--allow-no-vcs" "--allow-dirty" "--frozen" "--all" "--all-targets" "--message-format=json" "-Zfix-edition=start=2015", kill_on_drop: false }`
[INFO] [stderr]     Checking libloading v0.9.0
[INFO] [stderr]     Checking mio v1.2.0
[INFO] [stderr]     Checking socket2 v0.6.3
[INFO] [stderr]    Compiling tokio-macros v2.7.0
[INFO] [stderr]     Checking tokio v1.52.3
[INFO] [stderr]     Checking rust_essentials v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::fmt`
[INFO] [stdout]   --> src/macros.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 | use std::fmt;
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `w`
[INFO] [stdout]   --> src/data_types.rs:48:10
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let (w, _, z) = tup;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_w`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:48:16
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let (w, _, z) = tup;
[INFO] [stdout]    |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nums`
[INFO] [stdout]   --> src/data_types.rs:60:9
[INFO] [stdout]    |
[INFO] [stdout] 60 |     let nums: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_nums`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/smart_pointers.rs:19:14
[INFO] [stdout]    |
[INFO] [stdout] 19 |         Cons(i32, Box<List>),
[INFO] [stdout]    |         ---- ^^^  ^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `List` 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] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 19 -         Cons(i32, Box<List>),
[INFO] [stdout] 19 +         Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition value: `proptest`
[INFO] [stdout]    --> src/testing.rs:169:7
[INFO] [stdout]     |
[INFO] [stdout] 169 | #[cfg(feature = "proptest")]
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^ help: remove the condition
[INFO] [stdout]     |
[INFO] [stdout]     = note: no expected values for `feature`
[INFO] [stdout]     = help: consider adding `proptest` as a feature in `Cargo.toml`
[INFO] [stdout]     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout]     = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user2`
[INFO] [stdout]   --> src/structs_basics.rs:70:9
[INFO] [stdout]    |
[INFO] [stdout] 70 |     let user2 = User {
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `active` is never read
[INFO] [stdout]   --> src/structs_basics.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | struct User {
[INFO] [stdout]    |        ---- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 15 |     active: bool,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new_inactive` and `deactivate` are never used
[INFO] [stdout]   --> src/structs_basics.rs:29:8
[INFO] [stdout]    |
[INFO] [stdout] 18 | impl User {
[INFO] [stdout]    | --------- associated items in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 29 |     fn new_inactive(username: &str, email: &str) -> Self {
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     fn deactivate(mut self) -> Self {
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Point` is never constructed
[INFO] [stdout]   --> src/structs_basics.rs:53:8
[INFO] [stdout]    |
[INFO] [stdout] 53 | struct Point(i32, i32, i32);
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `can_hold` is never used
[INFO] [stdout]   --> src/structs_basics.rs:95:12
[INFO] [stdout]    |
[INFO] [stdout] 90 |     impl Rectangle {
[INFO] [stdout]    |     -------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 95 |         fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name` and `count` are never read
[INFO] [stdout]   --> src/macros.rs:58:5
[INFO] [stdout]    |
[INFO] [stdout] 57 | struct SimpleStruct {
[INFO] [stdout]    |        ------------ fields in this struct
[INFO] [stdout] 58 |     name: String,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 59 |     count: u32,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `SimpleStruct` 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 `panic_demo` is never used
[INFO] [stdout]   --> src/error_handling.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn panic_demo() {
[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 `read_username_from_file` is never used
[INFO] [stdout]   --> src/error_handling.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read_username_short` is never used
[INFO] [stdout]   --> src/error_handling.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_short() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `AppError` is never used
[INFO] [stdout]   --> src/error_handling.rs:52:6
[INFO] [stdout]    |
[INFO] [stdout] 52 | enum AppError {
[INFO] [stdout]    |      ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary `unsafe` block
[INFO] [stdout]    --> src/ffi.rs:106:5
[INFO] [stdout]     |
[INFO] [stdout] 106 |     unsafe { opaque_free(p) };
[INFO] [stdout]     |     ^^^^^^ unnecessary `unsafe` block
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_unsafe)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `w`
[INFO] [stdout]   --> src/data_types.rs:48:10
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let (w, _, z) = tup;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_w`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:48:16
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let (w, _, z) = tup;
[INFO] [stdout]    |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nums`
[INFO] [stdout]   --> src/data_types.rs:60:9
[INFO] [stdout]    |
[INFO] [stdout] 60 |     let nums: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_nums`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Clock` is never used
[INFO] [stdout]    --> src/testing.rs:125:7
[INFO] [stdout]     |
[INFO] [stdout] 125 | trait Clock {
[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 `RealClock` is never constructed
[INFO] [stdout]    --> src/testing.rs:130:8
[INFO] [stdout]     |
[INFO] [stdout] 130 | struct RealClock;
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `FakeClock` is never constructed
[INFO] [stdout]    --> src/testing.rs:141:8
[INFO] [stdout]     |
[INFO] [stdout] 141 | struct FakeClock(u64);
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Greeter` is never constructed
[INFO] [stdout]    --> src/testing.rs:148:8
[INFO] [stdout]     |
[INFO] [stdout] 148 | struct Greeter<C: Clock> {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `greet` are never used
[INFO] [stdout]    --> src/testing.rs:153:8
[INFO] [stdout]     |
[INFO] [stdout] 152 | impl<C: Clock> Greeter<C> {
[INFO] [stdout]     | ------------------------- associated items in this implementation
[INFO] [stdout] 153 |     fn new(clock: C) -> Self { Self { clock } }
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 154 |
[INFO] [stdout] 155 |     fn greet(&self) -> String {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary `unsafe` block
[INFO] [stdout]    --> src/ffi.rs:106:5
[INFO] [stdout]     |
[INFO] [stdout] 106 |     unsafe { opaque_free(p) };
[INFO] [stdout]     |     ^^^^^^ unnecessary `unsafe` block
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_unsafe)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Quit` and `ChangeColor` are never constructed
[INFO] [stdout]   --> src/enums_patterns.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout]  9 | enum Message {
[INFO] [stdout]    |      ------- variants in this enum
[INFO] [stdout] 10 |     Quit,                       // no data
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 13 |     ChangeColor(i32, i32, i32), // tuple-style
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Nickel` and `Dime` are never constructed
[INFO] [stdout]   --> src/enums_patterns.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 42 | enum Coin {
[INFO] [stdout]    |      ---- variants in this enum
[INFO] [stdout] 43 |     Penny,
[INFO] [stdout] 44 |     Nickel,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 45 |     Dime,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `panic_demo` is never used
[INFO] [stdout]   --> src/error_handling.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn panic_demo() {
[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 `read_username_from_file` is never used
[INFO] [stdout]   --> src/error_handling.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read_username_short` is never used
[INFO] [stdout]   --> src/error_handling.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_short() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `AppError` is never used
[INFO] [stdout]   --> src/error_handling.rs:52:6
[INFO] [stdout]    |
[INFO] [stdout] 52 | enum AppError {
[INFO] [stdout]    |      ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: use of unstable library feature `test`: `bench` is a part of custom test frameworks which are unstable
[INFO] [stdout]    --> src/testing.rs:196:7
[INFO] [stdout]     |
[INFO] [stdout] 196 |     #[bench]
[INFO] [stdout]     |       ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: see issue #50297 <https://github.com/rust-lang/rust/issues/50297> for more information
[INFO] [stdout]     = help: add `#![feature(test)]` to the crate attributes to enable
[INFO] [stdout]     = note: this compiler was built on 2026-06-16; consider upgrading it if it is out of date
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `test`
[INFO] [stdout]    --> src/testing.rs:194:9
[INFO] [stdout]     |
[INFO] [stdout] 194 |     use test::{Bencher, black_box};
[INFO] [stdout]     |         ^^^^ use of unresolved module or unlinked crate `test`
[INFO] [stdout]     |
[INFO] [stdout]     = help: if you wanted to use a crate named `test`, use `cargo add test` to add it to your `Cargo.toml`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition value: `proptest`
[INFO] [stdout]    --> src/testing.rs:169:7
[INFO] [stdout]     |
[INFO] [stdout] 169 | #[cfg(feature = "proptest")]
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^ help: remove the condition
[INFO] [stdout]     |
[INFO] [stdout]     = note: no expected values for `feature`
[INFO] [stdout]     = help: consider adding `proptest` as a feature in `Cargo.toml`
[INFO] [stdout]     = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout]     = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0432, E0658.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0432`.
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/concurrency.rs:29:17
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn channel_demo(mut rx: mpsc::Receiver<String>) {
[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] [stderr] error: could not compile `rust_essentials` (bin "testing" test) due to 2 previous errors; 1 warning emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused import: `std::fmt`
[INFO] [stdout]   --> src/macros.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 | use std::fmt;
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/concurrency.rs:29:17
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn channel_demo(mut rx: mpsc::Receiver<String>) {
[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: fields `0` and `1` are never read
[INFO] [stdout]   --> src/smart_pointers.rs:19:14
[INFO] [stdout]    |
[INFO] [stdout] 19 |         Cons(i32, Box<List>),
[INFO] [stdout]    |         ---- ^^^  ^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `List` 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] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 19 -         Cons(i32, Box<List>),
[INFO] [stdout] 19 +         Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `name` and `count` are never read
[INFO] [stdout]   --> src/macros.rs:58:5
[INFO] [stdout]    |
[INFO] [stdout] 57 | struct SimpleStruct {
[INFO] [stdout]    |        ------------ fields in this struct
[INFO] [stdout] 58 |     name: String,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 59 |     count: u32,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `SimpleStruct` 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: `user2`
[INFO] [stdout]   --> src/structs_basics.rs:70:9
[INFO] [stdout]    |
[INFO] [stdout] 70 |     let user2 = User {
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `active` is never read
[INFO] [stdout]   --> src/structs_basics.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | struct User {
[INFO] [stdout]    |        ---- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 15 |     active: bool,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new_inactive` and `deactivate` are never used
[INFO] [stdout]   --> src/structs_basics.rs:29:8
[INFO] [stdout]    |
[INFO] [stdout] 18 | impl User {
[INFO] [stdout]    | --------- associated items in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 29 |     fn new_inactive(username: &str, email: &str) -> Self {
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     fn deactivate(mut self) -> Self {
[INFO] [stdout]    |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Point` is never constructed
[INFO] [stdout]   --> src/structs_basics.rs:53:8
[INFO] [stdout]    |
[INFO] [stdout] 53 | struct Point(i32, i32, i32);
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `can_hold` is never used
[INFO] [stdout]   --> src/structs_basics.rs:95:12
[INFO] [stdout]    |
[INFO] [stdout] 90 |     impl Rectangle {
[INFO] [stdout]    |     -------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 95 |         fn can_hold(&self, other: &Rectangle) -> bool {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Quit` and `ChangeColor` are never constructed
[INFO] [stdout]   --> src/enums_patterns.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout]  9 | enum Message {
[INFO] [stdout]    |      ------- variants in this enum
[INFO] [stdout] 10 |     Quit,                       // no data
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 13 |     ChangeColor(i32, i32, i32), // tuple-style
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Nickel` and `Dime` are never constructed
[INFO] [stdout]   --> src/enums_patterns.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 42 | enum Coin {
[INFO] [stdout]    |      ---- variants in this enum
[INFO] [stdout] 43 |     Penny,
[INFO] [stdout] 44 |     Nickel,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 45 |     Dime,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83", kill_on_drop: false }`
[INFO] [stdout] 4623e596410ef95f63499e763aaeeab25a8cdfca482d10e5a75faa8047d84e83
