[INFO] cloning repository https://github.com/masa-matt/rust-tutrial
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/masa-matt/rust-tutrial" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmasa-matt%2Frust-tutrial", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmasa-matt%2Frust-tutrial'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f572f11c89d483c1e75e90de7350b967c35b7b45
[INFO] checking masa-matt/rust-tutrial against master#af4a5a13a15fa0c60e06321077ef452f769b42fd for pr-122960-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmasa-matt%2Frust-tutrial" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/masa-matt/rust-tutrial on toolchain af4a5a13a15fa0c60e06321077ef452f769b42fd
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+af4a5a13a15fa0c60e06321077ef452f769b42fd" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/masa-matt/rust-tutrial
[INFO] finished tweaking git repo https://github.com/masa-matt/rust-tutrial
[INFO] tweaked toml for git repo https://github.com/masa-matt/rust-tutrial written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/masa-matt/rust-tutrial 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" "+af4a5a13a15fa0c60e06321077ef452f769b42fd" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: virtual workspace defaulting to `resolver = "1"` despite one or more workspace members being on edition 2021 which implies `resolver = "2"`
[INFO] [stderr] note: to keep the current resolver, specify `workspace.resolver = "1"` in the workspace root's manifest
[INFO] [stderr] note: to use the edition 2021 resolver, specify `workspace.resolver = "2"` in the workspace root's manifest
[INFO] [stderr] note: for more details see https://doc.rust-lang.org/cargo/reference/resolver.html#resolver-versions
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rug v1.19.0
[INFO] [stderr]   Downloaded gmp-mpfr-sys v1.5.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+af4a5a13a15fa0c60e06321077ef452f769b42fd" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4fed809da311de5f1472cffe21dbdb650071dfe90965d9911da83aa968341e19
[INFO] running `Command { std: "docker" "start" "-a" "4fed809da311de5f1472cffe21dbdb650071dfe90965d9911da83aa968341e19", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4fed809da311de5f1472cffe21dbdb650071dfe90965d9911da83aa968341e19", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4fed809da311de5f1472cffe21dbdb650071dfe90965d9911da83aa968341e19", kill_on_drop: false }`
[INFO] [stdout] 4fed809da311de5f1472cffe21dbdb650071dfe90965d9911da83aa968341e19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+af4a5a13a15fa0c60e06321077ef452f769b42fd" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8ec60db58374d655e82fba8adf85604e80f6ac84fc46593f9fc29820f9337be9
[INFO] running `Command { std: "docker" "start" "-a" "8ec60db58374d655e82fba8adf85604e80f6ac84fc46593f9fc29820f9337be9", kill_on_drop: false }`
[INFO] [stderr] warning: virtual workspace defaulting to `resolver = "1"` despite one or more workspace members being on edition 2021 which implies `resolver = "2"`
[INFO] [stderr] note: to keep the current resolver, specify `workspace.resolver = "1"` in the workspace root's manifest
[INFO] [stderr] note: to use the edition 2021 resolver, specify `workspace.resolver = "2"` in the workspace root's manifest
[INFO] [stderr] note: for more details see https://doc.rust-lang.org/cargo/reference/resolver.html#resolver-versions
[INFO] [stderr]    Compiling gmp-mpfr-sys v1.5.0
[INFO] [stderr]    Compiling az v1.2.1
[INFO] [stderr]    Compiling rug v1.19.0
[INFO] [stderr]     Checking ch11-03-test-organization v0.1.0 (/opt/rustwide/workdir/ch11/ch11-03-test-organization)
[INFO] [stderr]     Checking ch04-03-slices v0.1.0 (/opt/rustwide/workdir/ch04/ch04-03-slices)
[INFO] [stderr]     Checking ch05-02-example-structs v0.1.0 (/opt/rustwide/workdir/ch05/ch05-02-example-structs)
[INFO] [stderr]     Checking ch05-01-defining-structs v0.1.0 (/opt/rustwide/workdir/ch05/ch05-01-defining-structs)
[INFO] [stderr]     Checking getrandom v0.2.8
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     let s = "Hello, world!";
[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: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 36 |     let word = string_slices_as_parameters(&my_string[0..6]);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let word = string_slices_as_parameters(&my_string[..]);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let word = first_word(&my_string);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let word = string_slices_as_parameters(&my_string_literal[0..6]);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let word = string_slices_as_parameters(&my_string_literal[..]);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let word = string_slices_as_parameters(my_string_literal);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_word`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user2`
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let user2 = build_user(String::from("someone@example.com"), String::from("someone"));
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user3`
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let user3 = User {
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_user3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let mut s = String::from("hello world");
[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: `black`
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let black = Color(0, 0, 0);
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_black`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `origin`
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let origin = Point(0, 0, 0);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_origin`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user`
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let user = UserWithReferences {
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_user`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `username`, `email`, `sign_in_count`, and `active` are never read
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 23 | struct User {
[INFO] [stdout]    |        ---- fields in this struct
[INFO] [stdout] 24 |     username: String,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 25 |     email: String,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 26 |     sign_in_count: u64,
[INFO] [stdout]    |     ^^^^^^^^^^^^^
[INFO] [stdout] 27 |     active: bool,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:42:18
[INFO] [stdout]    |
[INFO] [stdout] 42 |     struct Color(i32, i32, i32);
[INFO] [stdout]    |            ----- ^^^  ^^^  ^^^
[INFO] [stdout]    |            |
[INFO] [stdout]    |            fields in this struct
[INFO] [stdout]    |
[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] 42 |     struct Color((), (), ());
[INFO] [stdout]    |                  ~~  ~~  ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:69:9
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let slice = &s[0..2];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:76:9
[INFO] [stdout]    |
[INFO] [stdout] 76 |     let slice = &s[3..len];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> ch04/ch04-03-slices/src/main.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     let slice = &s[0..len];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0`, `1`, and `2` are never read
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:43:18
[INFO] [stdout]    |
[INFO] [stdout] 43 |     struct Point(i32, i32, i32);
[INFO] [stdout]    |            ----- ^^^  ^^^  ^^^
[INFO] [stdout]    |            |
[INFO] [stdout]    |            fields in this struct
[INFO] [stdout]    |
[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] 43 |     struct Point((), (), ());
[INFO] [stdout]    |                  ~~  ~~  ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `UserWithReferences` is never constructed
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:49:8
[INFO] [stdout]    |
[INFO] [stdout] 49 | struct UserWithReferences {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `struct_with_references` is never used
[INFO] [stdout]   --> ch05/ch05-01-defining-structs/src/main.rs:57:4
[INFO] [stdout]    |
[INFO] [stdout] 57 | fn struct_with_references() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ch06-03-if-let v0.1.0 (/opt/rustwide/workdir/ch06/ch06-03-if-let)
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ch11-01-writing-tests v0.1.0 (/opt/rustwide/workdir/ch11/ch11-01-writing-tests)
[INFO] [stderr]     Checking hello_cargo v0.1.0 (/opt/rustwide/workdir/ch01/ch01-03-hello-cargo)
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:14:13
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let mut count = 0;
[INFO] [stdout]    |             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_count` instead
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:17:14
[INFO] [stdout]    |
[INFO] [stdout] 17 |         _ => count += 1,
[INFO] [stdout]    |              ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let mut count = 0;
[INFO] [stdout]    |             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_count` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |         count += 1;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Alabama` and `Alaska` are never constructed
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:38:5
[INFO] [stdout]    |
[INFO] [stdout] 37 | enum UsState {
[INFO] [stdout]    |      ------- variants in this enum
[INFO] [stdout] 38 |     Alabama,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout] 39 |     Alaska,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Nickel`, `Dime`, and `Quarter` are never constructed
[INFO] [stdout]   --> ch06/ch06-03-if-let/src/main.rs:45:5
[INFO] [stdout]    |
[INFO] [stdout] 43 | enum Coin {
[INFO] [stdout]    |      ---- variants in this enum
[INFO] [stdout] 44 |     Penny,
[INFO] [stdout] 45 |     Nickel,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 46 |     Dime,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 47 |     Quarter(UsState),
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ch04-02-references-and-borrowing v0.1.0 (/opt/rustwide/workdir/ch04/ch04-02-references-and-borrowing)
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ch09-02-recoverable-errors-with-result v0.1.0 (/opt/rustwide/workdir/ch09/ch09-02-recoverable-errors-with-result)
[INFO] [stderr]     Checking ch10-03-lifetime-syntax v0.1.0 (/opt/rustwide/workdir/ch10/ch10-03-lifetime-syntax)
[INFO] [stdout] warning: unused variable: `name`
[INFO] [stdout]   --> ch11/ch11-01-writing-tests/src/lib.rs:23:17
[INFO] [stdout]    |
[INFO] [stdout] 23 | pub fn greeting(name: &str) -> String {
[INFO] [stdout]    |                 ^^^^ help: if this is intentional, prefix it with an underscore: `_name`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `value` is never read
[INFO] [stdout]   --> ch11/ch11-01-writing-tests/src/lib.rs:29:5
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub struct Guess {
[INFO] [stdout]    |            ----- field in this struct
[INFO] [stdout] 29 |     value: i32,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0106]: missing lifetime specifier
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:68:16
[INFO] [stdout]    |
[INFO] [stdout] 68 | fn dangle() -> &String {
[INFO] [stdout]    |                ^ expected named lifetime parameter
[INFO] [stdout]    |
[INFO] [stdout]    = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
[INFO] [stdout] help: consider using the `'static` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`
[INFO] [stdout]    |
[INFO] [stdout] 68 | fn dangle() -> &'static String {
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] help: instead, you are more likely to want to return an owned value
[INFO] [stdout]    |
[INFO] [stdout] 68 - fn dangle() -> &String {
[INFO] [stdout] 68 + fn dangle() -> String {
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking variables v0.1.0 (/opt/rustwide/workdir/ch03/ch03-01-variables-and-mutability)
[INFO] [stdout] warning: unused variable: `some_string`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:29:11
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn change(some_string: &String) {
[INFO] [stdout]    |           ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let r1 = &mut s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:50:13
[INFO] [stdout]    |
[INFO] [stdout] 50 |         let r1 = &mut s;
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:53:9
[INFO] [stdout]    |
[INFO] [stdout] 53 |     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: `r1`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:57:9
[INFO] [stdout]    |
[INFO] [stdout] 57 |     let r1 = &s2; // no problem
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r2`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let r2 = &s2; // no problem
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let mut s2 = String::from("hello");
[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: `reference_to_nothing`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let reference_to_nothing = dangle();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_reference_to_nothing`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0515]: cannot return reference to local variable `s`
[INFO] [stdout]   --> ch04/ch04-02-references-and-borrowing/src/main.rs:73:5
[INFO] [stdout]    |
[INFO] [stdout] 73 |     &s // we return a reference to the String, s
[INFO] [stdout]    |     ^^ returns a reference to data owned by the current function
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0106, E0515.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0106`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ch04-02-references-and-borrowing` (bin "ch04-02-references-and-borrowing") due to 3 previous errors; 8 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> ch10/ch10-03-lifetime-syntax/src/main.rs:73:9
[INFO] [stdout]    |
[INFO] [stdout] 73 |     let i = ImportantExcerpt {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> ch10/ch10-03-lifetime-syntax/src/main.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |     let s: &'static str = "I have a static lifetime.";
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let f = match f {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `part` is never read
[INFO] [stdout]   --> ch10/ch10-03-lifetime-syntax/src/main.rs:67:5
[INFO] [stdout]    |
[INFO] [stdout] 66 | struct ImportantExcerpt<'a> {
[INFO] [stdout]    |        ---------------- field in this struct
[INFO] [stdout] 67 |     part: &'a str,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `first_word` is never used
[INFO] [stdout]   --> ch10/ch10-03-lifetime-syntax/src/main.rs:79:4
[INFO] [stdout]    |
[INFO] [stdout] 79 | fn first_word(s: &str) -> &str {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:33:9
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let greeting_file = match greeting_file_result {
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `level` is never used
[INFO] [stdout]    --> ch10/ch10-03-lifetime-syntax/src/main.rs:103:8
[INFO] [stdout]     |
[INFO] [stdout] 101 | impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]     | ----------------------------- method in this implementation
[INFO] [stdout] 102 |     // no need to speficy, because of second rule.
[INFO] [stdout] 103 |     fn level(&self) -> i32 {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:48:9
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let f = File::open("hello.txt").unwrap();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `announce_and_return_part` is never used
[INFO] [stdout]    --> ch10/ch10-03-lifetime-syntax/src/main.rs:112:8
[INFO] [stdout]     |
[INFO] [stdout] 109 | impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]     | ----------------------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 112 |     fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let f = File::open("hello.txt").expect("Failed to open hello.txt");
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `static_lifetime` is never used
[INFO] [stdout]    --> ch10/ch10-03-lifetime-syntax/src/main.rs:118:4
[INFO] [stdout]     |
[INFO] [stdout] 118 | fn static_lifetime() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `generics_type_parameters_trait_bounds_liftimes` is never used
[INFO] [stdout]    --> ch10/ch10-03-lifetime-syntax/src/main.rs:122:4
[INFO] [stdout]     |
[INFO] [stdout] 122 | fn generics_type_parameters_trait_bounds_liftimes() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `type_result` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn type_result() {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_handling` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:30:4
[INFO] [stdout]    |
[INFO] [stdout] 30 | fn error_handling() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_unwrap` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn error_unwrap() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_expected` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn error_expected() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read_username_from_file` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:55:4
[INFO] [stdout]    |
[INFO] [stdout] 55 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_shortcut` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:71:4
[INFO] [stdout]    |
[INFO] [stdout] 71 | fn error_shortcut() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_shortcut_shorter` is never used
[INFO] [stdout]   --> ch09/ch09-02-recoverable-errors-with-result/src/main.rs:78:4
[INFO] [stdout]    |
[INFO] [stdout] 78 | fn error_shortcut_shorter() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "8ec60db58374d655e82fba8adf85604e80f6ac84fc46593f9fc29820f9337be9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8ec60db58374d655e82fba8adf85604e80f6ac84fc46593f9fc29820f9337be9", kill_on_drop: false }`
[INFO] [stdout] 8ec60db58374d655e82fba8adf85604e80f6ac84fc46593f9fc29820f9337be9