[INFO] cloning repository https://github.com/Medsko/study-crate
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Medsko/study-crate" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMedsko%2Fstudy-crate", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMedsko%2Fstudy-crate'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0cc2263369144822efe27caeeda5c4d1ce201581
[INFO] checking Medsko/study-crate against master#5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMedsko%2Fstudy-crate" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Medsko/study-crate on toolchain 5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Medsko/study-crate
[INFO] finished tweaking git repo https://github.com/Medsko/study-crate
[INFO] tweaked toml for git repo https://github.com/Medsko/study-crate written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/Medsko/study-crate already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 478fdbf99424e21dfe988b5b32756df42e77fedccf9d23db05bb157d569b58f5
[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" "478fdbf99424e21dfe988b5b32756df42e77fedccf9d23db05bb157d569b58f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "478fdbf99424e21dfe988b5b32756df42e77fedccf9d23db05bb157d569b58f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "478fdbf99424e21dfe988b5b32756df42e77fedccf9d23db05bb157d569b58f5", kill_on_drop: false }`
[INFO] [stdout] 478fdbf99424e21dfe988b5b32756df42e77fedccf9d23db05bb157d569b58f5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d557bf3bd1c47f1b1150ed3287ce3128a64a0d7f236ffbb43051cd0be3c5d6ce
[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" "d557bf3bd1c47f1b1150ed3287ce3128a64a0d7f236ffbb43051cd0be3c5d6ce", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking ppv-lite86 v0.2.8
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking study-crate v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/lib.rs:23:39
[INFO] [stdout]    |
[INFO] [stdout] 23 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/collections/vectors.rs:35:39
[INFO] [stdout]    |
[INFO] [stdout] 35 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `exercise`
[INFO] [stdout]  --> src/collections/exercises.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 | pub fn exercise() {
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `employee_registration`
[INFO] [stdout]   --> src/collections/exercises.rs:35:8
[INFO] [stdout]    |
[INFO] [stdout] 35 | pub fn employee_registration() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `remove_employee`
[INFO] [stdout]   --> src/collections/exercises.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn remove_employee(register: &mut HashMap<String, Vec<String>>, other_words: &mut SplitWhitespace) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `extract_full_name`
[INFO] [stdout]   --> src/collections/exercises.rs:90:4
[INFO] [stdout]    |
[INFO] [stdout] 90 | fn extract_full_name(words: &mut SplitWhitespace, stop: &str) -> Result<String, String> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `register_employee`
[INFO] [stdout]    --> src/collections/exercises.rs:108:4
[INFO] [stdout]     |
[INFO] [stdout] 108 | fn register_employee(register: &mut HashMap<String, Vec<String>>, other_words: &mut SplitWhitespace) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `print_register`
[INFO] [stdout]    --> src/collections/exercises.rs:119:4
[INFO] [stdout]     |
[INFO] [stdout] 119 | fn print_register(register: &HashMap<String, Vec<String>>) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `hash_it_up`
[INFO] [stdout]  --> src/collections/hashmaps.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub fn hash_it_up() {
[INFO] [stdout]   |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `string_stuff`
[INFO] [stdout]  --> src/collections/strings.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn string_stuff() {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `got_game`
[INFO] [stdout]   --> src/collections/strings.rs:22:4
[INFO] [stdout]    |
[INFO] [stdout] 22 | fn got_game() -> String {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/lib.rs:23:39
[INFO] [stdout]    |
[INFO] [stdout] 23 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/collections/vectors.rs:35:39
[INFO] [stdout]    |
[INFO] [stdout] 35 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `exercise`
[INFO] [stdout]  --> src/collections/exercises.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 | pub fn exercise() {
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `employee_registration`
[INFO] [stdout]   --> src/collections/exercises.rs:35:8
[INFO] [stdout]    |
[INFO] [stdout] 35 | pub fn employee_registration() {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `remove_employee`
[INFO] [stdout]   --> src/collections/exercises.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn remove_employee(register: &mut HashMap<String, Vec<String>>, other_words: &mut SplitWhitespace) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `extract_full_name`
[INFO] [stdout]   --> src/collections/exercises.rs:90:4
[INFO] [stdout]    |
[INFO] [stdout] 90 | fn extract_full_name(words: &mut SplitWhitespace, stop: &str) -> Result<String, String> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `register_employee`
[INFO] [stdout]    --> src/collections/exercises.rs:108:4
[INFO] [stdout]     |
[INFO] [stdout] 108 | fn register_employee(register: &mut HashMap<String, Vec<String>>, other_words: &mut SplitWhitespace) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `print_register`
[INFO] [stdout]    --> src/collections/exercises.rs:119:4
[INFO] [stdout]     |
[INFO] [stdout] 119 | fn print_register(register: &HashMap<String, Vec<String>>) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `hash_it_up`
[INFO] [stdout]  --> src/collections/hashmaps.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub fn hash_it_up() {
[INFO] [stdout]   |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `string_stuff`
[INFO] [stdout]  --> src/collections/strings.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 2 | pub fn string_stuff() {
[INFO] [stdout]   |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `got_game`
[INFO] [stdout]   --> src/collections/strings.rs:22:4
[INFO] [stdout]    |
[INFO] [stdout] 22 | fn got_game() -> String {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `to_pig_latin`
[INFO] [stdout]   --> src/collections/strings.rs:33:8
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub fn to_pig_latin(kosher: &String) -> String {
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `is_vowel`
[INFO] [stdout]   --> src/collections/strings.rs:53:4
[INFO] [stdout]    |
[INFO] [stdout] 53 | fn is_vowel(maybe_vowel: &char) -> bool {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `SystemTimeError`
[INFO] [stdout]   --> src/fp/closures.rs:79:33
[INFO] [stdout]    |
[INFO] [stdout] 79 |     use std::time::{SystemTime, SystemTimeError};
[INFO] [stdout]    |                                 ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `yet_another_string`
[INFO] [stdout]   --> src/prepackages/ownership.rs:69:9
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let yet_another_string = "Hi".to_string();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_yet_another_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `immutable_pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:75:9
[INFO] [stdout]    |
[INFO] [stdout] 75 |     let immutable_pointer = &yet_another_string;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_immutable_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `another_immutable_pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:76:9
[INFO] [stdout]    |
[INFO] [stdout] 76 |     let another_immutable_pointer = &yet_another_string;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_another_immutable_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:78:9
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let pointer = &mut yet_another_string;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_first_four_chars`
[INFO] [stdout]    --> src/prepackages/ownership.rs:111:9
[INFO] [stdout]     |
[INFO] [stdout] 111 |     let splice_first_four_chars = &s[0..4];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_first_four_chars`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_first_four_chars_also`
[INFO] [stdout]    --> src/prepackages/ownership.rs:112:9
[INFO] [stdout]     |
[INFO] [stdout] 112 |     let splice_first_four_chars_also = &s[..4];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_first_four_chars_also`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_chars_from_fourth`
[INFO] [stdout]    --> src/prepackages/ownership.rs:114:9
[INFO] [stdout]     |
[INFO] [stdout] 114 |     let splice_chars_from_fourth = &s[4..];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_chars_from_fourth`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second_user`
[INFO] [stdout]   --> src/prepackages/structs.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let second_user = User {
[INFO] [stdout]    |         ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_second_user`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:44:9
[INFO] [stdout]    |
[INFO] [stdout] 44 |     let four = IpAddrKind::V4;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `hip`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let hip = IpAddrKind::V6;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_hip`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:47:9
[INFO] [stdout]    |
[INFO] [stdout] 47 |     let loopback = IpAddr {
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `concise_loopback`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let concise_loopback = ConciseIpAddr::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_concise_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let home = ConciseIpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/collections/vectors.rs:35:39
[INFO] [stdout]    |
[INFO] [stdout] 35 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nums`
[INFO] [stdout]   --> src/fp/closures.rs:52:10
[INFO] [stdout]    |
[INFO] [stdout] 52 |         |nums| {
[INFO] [stdout]    |          ^^^^ help: if this is intentional, prefix it with an underscore: `_nums`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num`
[INFO] [stdout]   --> src/fp/closures.rs:49:6
[INFO] [stdout]    |
[INFO] [stdout] 49 |     |num| {
[INFO] [stdout]    |      ^^^ help: if this is intentional, prefix it with an underscore: `_num`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num`
[INFO] [stdout]   --> src/fp/closures.rs:59:45
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let mut expensive_result = Cacher::new(|num| {
[INFO] [stdout]    |                                             ^^^ help: if this is intentional, prefix it with an underscore: `_num`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 17 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `yet_another_string`
[INFO] [stdout]   --> src/prepackages/ownership.rs:69:9
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let yet_another_string = "Hi".to_string();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_yet_another_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `immutable_pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:75:9
[INFO] [stdout]    |
[INFO] [stdout] 75 |     let immutable_pointer = &yet_another_string;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_immutable_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `another_immutable_pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:76:9
[INFO] [stdout]    |
[INFO] [stdout] 76 |     let another_immutable_pointer = &yet_another_string;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_another_immutable_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `pointer`
[INFO] [stdout]   --> src/prepackages/ownership.rs:78:9
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let pointer = &mut yet_another_string;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_pointer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_first_four_chars`
[INFO] [stdout]    --> src/prepackages/ownership.rs:111:9
[INFO] [stdout]     |
[INFO] [stdout] 111 |     let splice_first_four_chars = &s[0..4];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_first_four_chars`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_first_four_chars_also`
[INFO] [stdout]    --> src/prepackages/ownership.rs:112:9
[INFO] [stdout]     |
[INFO] [stdout] 112 |     let splice_first_four_chars_also = &s[..4];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_first_four_chars_also`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `splice_chars_from_fourth`
[INFO] [stdout]    --> src/prepackages/ownership.rs:114:9
[INFO] [stdout]     |
[INFO] [stdout] 114 |     let splice_chars_from_fourth = &s[4..];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_splice_chars_from_fourth`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second_user`
[INFO] [stdout]   --> src/prepackages/structs.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let second_user = User {
[INFO] [stdout]    |         ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_second_user`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `four`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:44:9
[INFO] [stdout]    |
[INFO] [stdout] 44 |     let four = IpAddrKind::V4;
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `hip`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let hip = IpAddrKind::V6;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_hip`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:47:9
[INFO] [stdout]    |
[INFO] [stdout] 47 |     let loopback = IpAddr {
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `concise_loopback`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let concise_loopback = ConciseIpAddr::V6(String::from("::1"));
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_concise_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/prepackages/enums/enums.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let home = ConciseIpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `key`
[INFO] [stdout]   --> src/collections/vectors.rs:35:39
[INFO] [stdout]    |
[INFO] [stdout] 35 |     match counts.iter().max_by_key(|&(key, value)| value) {
[INFO] [stdout]    |                                       ^^^ help: if this is intentional, prefix it with an underscore: `_key`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nums`
[INFO] [stdout]   --> src/fp/closures.rs:52:10
[INFO] [stdout]    |
[INFO] [stdout] 52 |         |nums| {
[INFO] [stdout]    |          ^^^^ help: if this is intentional, prefix it with an underscore: `_nums`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num`
[INFO] [stdout]   --> src/fp/closures.rs:49:6
[INFO] [stdout]    |
[INFO] [stdout] 49 |     |num| {
[INFO] [stdout]    |      ^^^ help: if this is intentional, prefix it with an underscore: `_num`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num`
[INFO] [stdout]   --> src/fp/closures.rs:59:45
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let mut expensive_result = Cacher::new(|num| {
[INFO] [stdout]    |                                             ^^^ help: if this is intentional, prefix it with an underscore: `_num`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]    --> src/fp/closures.rs:118:13
[INFO] [stdout]     |
[INFO] [stdout] 118 |         let v1 = c.value(1);
[INFO] [stdout]     |             ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 19 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.90s
[INFO] running `Command { std: "docker" "inspect" "d557bf3bd1c47f1b1150ed3287ce3128a64a0d7f236ffbb43051cd0be3c5d6ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d557bf3bd1c47f1b1150ed3287ce3128a64a0d7f236ffbb43051cd0be3c5d6ce", kill_on_drop: false }`
[INFO] [stdout] d557bf3bd1c47f1b1150ed3287ce3128a64a0d7f236ffbb43051cd0be3c5d6ce