[INFO] cloning repository https://github.com/dansaldt/rustbook
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/dansaldt/rustbook" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdansaldt%2Frustbook", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdansaldt%2Frustbook'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 89031e10c5cc1e5ae7b9a9075bd03d7e0106fc23
[INFO] checking dansaldt/rustbook against master#a5f164faad4a2fed606b8160fd7ecd2d5cbba381 for pr-84920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdansaldt%2Frustbook" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/dansaldt/rustbook on toolchain a5f164faad4a2fed606b8160fd7ecd2d5cbba381
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/dansaldt/rustbook
[INFO] finished tweaking git repo https://github.com/dansaldt/rustbook
[INFO] tweaked toml for git repo https://github.com/dansaldt/rustbook written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/dansaldt/rustbook already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 35a494ee73fae736a691c5f339c98bab9527ca023bd4d30e5cf8795d632844ce
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "35a494ee73fae736a691c5f339c98bab9527ca023bd4d30e5cf8795d632844ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "35a494ee73fae736a691c5f339c98bab9527ca023bd4d30e5cf8795d632844ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "35a494ee73fae736a691c5f339c98bab9527ca023bd4d30e5cf8795d632844ce", kill_on_drop: false }`
[INFO] [stdout] 35a494ee73fae736a691c5f339c98bab9527ca023bd4d30e5cf8795d632844ce
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e2738cbff017f2e6582670e462972063d6f83d75c47549d842f80e8f9ad5e9ca
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "e2738cbff017f2e6582670e462972063d6f83d75c47549d842f80e8f9ad5e9ca", kill_on_drop: false }`
[INFO] [stderr]     Checking oop v0.1.0 (/opt/rustwide/workdir/oop)
[INFO] [stderr]     Checking rust_book v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking generics-traits-lifetimes v0.1.0 (/opt/rustwide/workdir/generics-traits-lifetimes)
[INFO] [stderr]     Checking restaurant v0.1.0 (/opt/rustwide/workdir/restaurant)
[INFO] [stderr]     Checking err-handling v0.1.0 (/opt/rustwide/workdir/err-handling)
[INFO] [stdout] warning: unnecessary parentheses around `if` condition
[INFO] [stdout]  --> generics-traits-lifetimes/src/lifetimes.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 |     if (x.len() > y.len()) {
[INFO] [stdout]   |        ^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0106]: missing lifetime specifier
[INFO] [stdout]   --> src/main.rs:32:17
[INFO] [stdout]    |
[INFO] [stdout] 32 | 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
[INFO] [stdout]    |
[INFO] [stdout] 32 | fn dangle () -> &'static String
[INFO] [stdout]    |                 ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0106`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let six = plus_one(five);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let none = plus_one(None);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alabama`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Alabama,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_book`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: variant is never constructed: `Penny`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     Penny,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 |     Nickel,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Dime`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     Dime,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0106]: missing lifetime specifier
[INFO] [stdout]   --> src/main.rs:32:17
[INFO] [stdout]    |
[INFO] [stdout] 32 | 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
[INFO] [stdout]    |
[INFO] [stdout] 32 | fn dangle () -> &'static String
[INFO] [stdout]    |                 ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0106`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     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: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let f = File::open("hello.txt").unwrap_or_else(|error| {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     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: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |     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: unused variable: `res`
[INFO] [stdout]    --> err-handling/src/recoverable-errors.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let res = read_username_from_file_v3().expect("Failed to read username");
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_res`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     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: function is never used: `open_or_create_file`
[INFO] [stdout]  --> err-handling/src/recoverable-errors.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn open_or_create_file () {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_or_create_file_more_concise_impl`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:24:4
[INFO] [stdout]    |
[INFO] [stdout] 24 | fn open_or_create_file_more_concise_impl () {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_file_unwrap`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn open_file_unwrap() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_file_expect`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:40:4
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn open_file_expect() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v2`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:62:4
[INFO] [stdout]    |
[INFO] [stdout] 62 | fn read_username_from_file_v2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v4`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:94:4
[INFO] [stdout]    |
[INFO] [stdout] 94 | fn read_username_from_file_v4() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let f = File::open("hello.txt").unwrap_or_else(|error| {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     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: unused variable: `f`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |     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: unused variable: `res`
[INFO] [stdout]    --> err-handling/src/recoverable-errors.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let res = read_username_from_file_v3().expect("Failed to read username");
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_res`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]  --> src/ch8/ch-8.1-vector.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let v1 = vec![1, 2, 3];
[INFO] [stdout]   |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         let v = vec![1, 2, 3];
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:81:13
[INFO] [stdout]    |
[INFO] [stdout] 81 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_or_create_file`
[INFO] [stdout]  --> err-handling/src/recoverable-errors.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn open_or_create_file () {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_or_create_file_more_concise_impl`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:24:4
[INFO] [stdout]    |
[INFO] [stdout] 24 | fn open_or_create_file_more_concise_impl () {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_file_unwrap`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn open_file_unwrap() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `open_file_expect`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:40:4
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn open_file_expect() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v2`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:62:4
[INFO] [stdout]    |
[INFO] [stdout] 62 | fn read_username_from_file_v2() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file_v4`
[INFO] [stdout]   --> err-handling/src/recoverable-errors.rs:94:4
[INFO] [stdout]    |
[INFO] [stdout] 94 | fn read_username_from_file_v4() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item1`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:63:17
[INFO] [stdout]    |
[INFO] [stdout] 63 | pub fn notify3 (item1: &impl Summary, item2: &impl Summary) {
[INFO] [stdout]    |                 ^^^^^ help: if this is intentional, prefix it with an underscore: `_item1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:45:13
[INFO] [stdout]    |
[INFO] [stdout] 45 |         let mut v = vec![1, 2, 3, 4, 5];
[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: 12 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item2`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:63:39
[INFO] [stdout]    |
[INFO] [stdout] 63 | pub fn notify3 (item1: &impl Summary, item2: &impl Summary) {
[INFO] [stdout]    |                                       ^^^^^ help: if this is intentional, prefix it with an underscore: `_item2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item1`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:67:29
[INFO] [stdout]    |
[INFO] [stdout] 67 | pub fn notify4<T: Summary> (item1: &T, item2: &T) {
[INFO] [stdout]    |                             ^^^^^ help: if this is intentional, prefix it with an underscore: `_item1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item2`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:67:40
[INFO] [stdout]    |
[INFO] [stdout] 67 | pub fn notify4<T: Summary> (item1: &T, item2: &T) {
[INFO] [stdout]    |                                        ^^^^^ help: if this is intentional, prefix it with an underscore: `_item2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:72:17
[INFO] [stdout]    |
[INFO] [stdout] 72 | pub fn notify5 (item: &(impl Summary + Display)) {
[INFO] [stdout]    |                 ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:75:40
[INFO] [stdout]    |
[INFO] [stdout] 75 | pub fn notify6 <T: Summary + Display> (item: &T) {
[INFO] [stdout]    |                                        ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:80:56
[INFO] [stdout]    |
[INFO] [stdout] 80 | fn some_function<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32 {
[INFO] [stdout]    |                                                        ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:80:63
[INFO] [stdout]    |
[INFO] [stdout] 80 | fn some_function<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32 {
[INFO] [stdout]    |                                                               ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:84:26
[INFO] [stdout]    |
[INFO] [stdout] 84 | fn some_function2<T, U> (t: &T, u: &U) -> i32
[INFO] [stdout]    |                          ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:84:33
[INFO] [stdout]    |
[INFO] [stdout] 84 | fn some_function2<T, U> (t: &T, u: &U) -> i32
[INFO] [stdout]    |                                 ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let six = plus_one(five);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let none = plus_one(None);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Alabama`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Alabama,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Penny`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     Penny,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Nickel`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 |     Nickel,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Dime`
[INFO] [stdout]   --> src/ch6/ch-6.2-match-control-flow-operator.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     Dime,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `some_function`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:80:4
[INFO] [stdout]    |
[INFO] [stdout] 80 | fn some_function<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]  --> src/ch8/ch-8.1-vector.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let v1 = vec![1, 2, 3];
[INFO] [stdout]   |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         let v = vec![1, 2, 3];
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `row`
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:81:13
[INFO] [stdout]    |
[INFO] [stdout] 81 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/ch8/ch-8.1-vector.rs:45:13
[INFO] [stdout]    |
[INFO] [stdout] 45 |         let mut v = vec![1, 2, 3, 4, 5];
[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: function is never used: `some_function2`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:84:4
[INFO] [stdout]    |
[INFO] [stdout] 84 | fn some_function2<T, U> (t: &T, u: &U) -> i32
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `returns_summarizable`
[INFO] [stdout]   --> generics-traits-lifetimes/src/traits.rs:92:4
[INFO] [stdout]    |
[INFO] [stdout] 92 | fn returns_summarizable() -> impl Summary {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Pair`
[INFO] [stdout]    --> generics-traits-lifetimes/src/traits.rs:113:8
[INFO] [stdout]     |
[INFO] [stdout] 113 | struct Pair <T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]    --> generics-traits-lifetimes/src/traits.rs:119:8
[INFO] [stdout]     |
[INFO] [stdout] 119 |     fn new (x: T, y: T) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `cmp_display`
[INFO] [stdout]    --> generics-traits-lifetimes/src/traits.rs:125:8
[INFO] [stdout]     |
[INFO] [stdout] 125 |     fn cmp_display(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 12 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 16 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "e2738cbff017f2e6582670e462972063d6f83d75c47549d842f80e8f9ad5e9ca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e2738cbff017f2e6582670e462972063d6f83d75c47549d842f80e8f9ad5e9ca", kill_on_drop: false }`
[INFO] [stdout] e2738cbff017f2e6582670e462972063d6f83d75c47549d842f80e8f9ad5e9ca