[INFO] cloning repository https://github.com/johnshift/rust-ds
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/johnshift/rust-ds" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjohnshift%2Frust-ds", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjohnshift%2Frust-ds'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 847ffdcbeeec919343eb397e689e60606b0bd8a3
[INFO] checking johnshift/rust-ds against try#0611f7de057c584b8771102fde7aed6c70c71d3b for pr-146440
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjohnshift%2Frust-ds" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/johnshift/rust-ds
[INFO] finished tweaking git repo https://github.com/johnshift/rust-ds
[INFO] tweaked toml for git repo https://github.com/johnshift/rust-ds written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/johnshift/rust-ds on toolchain 0611f7de057c584b8771102fde7aed6c70c71d3b
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/johnshift/rust-ds 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" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6e04e5d138fe02f35e34ab4d4f27fcb37aaa5e0749e0775b566694aa9150f0bd
[INFO] running `Command { std: "docker" "start" "-a" "6e04e5d138fe02f35e34ab4d4f27fcb37aaa5e0749e0775b566694aa9150f0bd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6e04e5d138fe02f35e34ab4d4f27fcb37aaa5e0749e0775b566694aa9150f0bd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6e04e5d138fe02f35e34ab4d4f27fcb37aaa5e0749e0775b566694aa9150f0bd", kill_on_drop: false }`
[INFO] [stdout] 6e04e5d138fe02f35e34ab4d4f27fcb37aaa5e0749e0775b566694aa9150f0bd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 96cffde7c99a6df0a913b7f08b9447a7febfddbdfc57cae424966a3904f3742d
[INFO] running `Command { std: "docker" "start" "-a" "96cffde7c99a6df0a913b7f08b9447a7febfddbdfc57cae424966a3904f3742d", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver v1.0.4
[INFO] [stderr]    Compiling serde v1.0.127
[INFO] [stderr]    Compiling crossbeam-utils v0.8.5
[INFO] [stderr]    Compiling libc v0.2.99
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling rayon-core v1.9.1
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]     Checking itoa v0.4.7
[INFO] [stderr]    Compiling serde_json v1.0.66
[INFO] [stderr]    Compiling syn v1.0.74
[INFO] [stderr]     Checking either v1.6.1
[INFO] [stderr]    Compiling rayon v1.5.1
[INFO] [stderr]     Checking regex-automata v0.1.10
[INFO] [stderr]     Checking plotters-backend v0.3.2
[INFO] [stderr]    Compiling serde_derive v1.0.127
[INFO] [stderr]     Checking regex-syntax v0.6.25
[INFO] [stderr]     Checking half v1.7.1
[INFO] [stderr]     Checking itertools v0.10.1
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]     Checking hashmap v0.1.0 (/opt/rustwide/workdir/hashmap)
[INFO] [stderr]     Checking trees v0.1.0 (/opt/rustwide/workdir/trees)
[INFO] [stderr]     Checking array v0.1.0 (/opt/rustwide/workdir/array)
[INFO] [stdout] warning: struct `MyArray` is never constructed
[INFO] [stdout]   --> array/src/lib.rs:10:8
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct MyArray<T> {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `get`, `push`, `pop`, and `delete` are never used
[INFO] [stdout]   --> array/src/lib.rs:16:6
[INFO] [stdout]    |
[INFO] [stdout] 15 | impl<T> MyArray<T> {
[INFO] [stdout]    | ------------------ associated items in this implementation
[INFO] [stdout] 16 |   fn new(data: Vec<T>) -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 23 |   fn get(&self, index: usize) -> Option<&T> {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 28 |   fn push(&mut self, item: T) -> usize {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 35 |   fn pop(&mut self) -> Option<T> {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 40 |   fn delete(&mut self, index: usize) -> Option<T> {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `array_exercise1` is never used
[INFO] [stdout]  --> array/src/exercise.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn array_exercise1<T: Ord>(a1: Vec<T>, a2: Vec<T>) -> Vec<T> {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ref-deref v0.1.0 (/opt/rustwide/workdir/ref-deref)
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]  --> trees/src/binary_tree.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Node<T: Ord> {
[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 function `new` is never used
[INFO] [stdout]   --> trees/src/binary_tree.rs:11:6
[INFO] [stdout]    |
[INFO] [stdout] 10 | impl<T: Ord> Node<T> {
[INFO] [stdout]    | -------------------- associated function in this implementation
[INFO] [stdout] 11 |   fn new(value: T) -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Tree` is never constructed
[INFO] [stdout]   --> trees/src/binary_tree.rs:21:8
[INFO] [stdout]    |
[INFO] [stdout] 21 | struct Tree<T: Ord>(Option<Box<Node<T>>>);
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `insert`, and `has` are never used
[INFO] [stdout]   --> trees/src/binary_tree.rs:24:6
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl<T: Ord> Tree<T> {
[INFO] [stdout]    | -------------------- associated items in this implementation
[INFO] [stdout] 24 |   fn new(value: T) -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 28 |   fn insert(&mut self, value: T) {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 42 |   fn has(&self, value: T) -> bool {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking plotters-svg v0.3.1
[INFO] [stderr]     Checking fntools v0.1.0 (/opt/rustwide/workdir/fntools)
[INFO] [stdout] warning: struct `TODO` is never constructed
[INFO] [stdout]  --> ref-deref/src/lib.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 | struct TODO;
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking iterators v0.1.0 (/opt/rustwide/workdir/iterators)
[INFO] [stdout] warning: struct `TODO` is never constructed
[INFO] [stdout]   --> iterators/src/lib.rs:19:8
[INFO] [stdout]    |
[INFO] [stdout] 19 | struct TODO;
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking linked-list v0.1.0 (/opt/rustwide/workdir/linked-list)
[INFO] [stdout] warning: struct `TODO` is never constructed
[INFO] [stdout]   --> iterators/src/lib.rs:19:8
[INFO] [stdout]    |
[INFO] [stdout] 19 | struct TODO;
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around closure body
[INFO] [stdout]  --> fntools/src/filter.rs:8:40
[INFO] [stdout]   |
[INFO] [stdout] 8 |   for i in (start..end + 1).filter(|n| (n % x == 0 && *n != 0)) {
[INFO] [stdout]   |                                        ^                     ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]   |
[INFO] [stdout] 8 -   for i in (start..end + 1).filter(|n| (n % x == 0 && *n != 0)) {
[INFO] [stdout] 8 +   for i in (start..end + 1).filter(|n| n % x == 0 && *n != 0) {
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `filter_demo` is never used
[INFO] [stdout]  --> fntools/src/filter.rs:4:4
[INFO] [stdout]   |
[INFO] [stdout] 4 | fn filter_demo(start: usize, end: usize, x: usize) -> Vec<usize> {
[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 `fold_startend` is never used
[INFO] [stdout]  --> fntools/src/fold.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn fold_startend(start: i32, end: i32) -> i32 {
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `map_squared` is never used
[INFO] [stdout]  --> fntools/src/map.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn map_squared(a: Vec<i32>) -> Vec<i32> {
[INFO] [stdout]   |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `reverse` is never used
[INFO] [stdout]  --> fntools/src/rev.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn reverse<T>(arr: Vec<T>) -> Vec<T> {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `zip_demo` is never used
[INFO] [stdout]  --> fntools/src/zip.rs:3:8
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub fn zip_demo<T>(arr1: Vec<T>, arr2: Vec<T>)
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `zip_merge` is never used
[INFO] [stdout]   --> fntools/src/zip.rs:17:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | pub fn zip_merge<T>(arr1: Vec<T>, arr2: Vec<T>) -> Vec<T>
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around closure body
[INFO] [stdout]  --> fntools/src/filter.rs:8:40
[INFO] [stdout]   |
[INFO] [stdout] 8 |   for i in (start..end + 1).filter(|n| (n % x == 0 && *n != 0)) {
[INFO] [stdout]   |                                        ^                     ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]   |
[INFO] [stdout] 8 -   for i in (start..end + 1).filter(|n| (n % x == 0 && *n != 0)) {
[INFO] [stdout] 8 +   for i in (start..end + 1).filter(|n| n % x == 0 && *n != 0) {
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `TODO` is never constructed
[INFO] [stdout]  --> ref-deref/src/lib.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 | struct TODO;
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking stacks-queues v0.1.0 (/opt/rustwide/workdir/stacks-queues)
[INFO] [stdout] warning: struct `SinglyLinkedList` is never constructed
[INFO] [stdout]   --> linked-list/src/lib.rs:24:8
[INFO] [stdout]    |
[INFO] [stdout] 24 | struct SinglyLinkedList<T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: multiple associated items are never used
[INFO] [stdout]   --> linked-list/src/lib.rs:29:6
[INFO] [stdout]    |
[INFO] [stdout] 28 | impl<T: Sized> SinglyLinkedList<T> {
[INFO] [stdout]    | ---------------------------------- associated items in this implementation
[INFO] [stdout] 29 |   fn new(value: T) -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 35 |   fn len(&self) -> usize {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 42 |   fn head(&self) -> Option<&T> {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 52 |   fn tail(&self) -> Option<&T> {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 61 |   fn append(&mut self, value: T) {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 66 |   fn prepend(&mut self, value: T) {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 73 |   fn insert(&mut self, index: usize, value: T) {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 78 |   fn remove(&mut self, index: usize) {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 83 |   fn reverse(&mut self) {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `LinkedList` is never constructed
[INFO] [stdout]   --> linked-list/src/bad_linked_list.rs:21:12
[INFO] [stdout]    |
[INFO] [stdout] 21 | pub struct LinkedList {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout]    = note: `#[deny(unused_unconstructable_pub_struct)]` (part of `#[deny(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `value` and `next` are never read
[INFO] [stdout]   --> linked-list/src/bad_linked_list.rs:17:3
[INFO] [stdout]    |
[INFO] [stdout] 15 | pub struct Node {
[INFO] [stdout]    |            ---- fields in this struct
[INFO] [stdout] 16 |   // final size: 16 bytes -> largest=8bytes multipled by two fields
[INFO] [stdout] 17 |   value: i32, // 4 bytes
[INFO] [stdout]    |   ^^^^^
[INFO] [stdout] 18 |   next: Link, // 8 bytes
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `head` is never read
[INFO] [stdout]   --> linked-list/src/bad_linked_list.rs:23:3
[INFO] [stdout]    |
[INFO] [stdout] 21 | pub struct LinkedList {
[INFO] [stdout]    |            ---------- field in this struct
[INFO] [stdout] 22 |   // final size: 8 bytes
[INFO] [stdout] 23 |   head: Link, // Link -> 8 bytes
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `prepend`, and `pop` are never used
[INFO] [stdout]   --> linked-list/src/bad_linked_list.rs:27:6
[INFO] [stdout]    |
[INFO] [stdout] 26 | impl LinkedList {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 27 |   fn new() -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 32 |   fn prepend(&mut self, value: i32) {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 51 |   fn pop(&mut self) -> Option<i32> {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `List` is never constructed
[INFO] [stdout]   --> linked-list/src/better_linked_list.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 | pub struct List<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `Iter` is never constructed
[INFO] [stdout]   --> linked-list/src/better_linked_list.rs:43:12
[INFO] [stdout]    |
[INFO] [stdout] 43 | pub struct Iter<'a, T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `prepend`, `tail`, and `head` are never used
[INFO] [stdout]   --> linked-list/src/better_linked_list.rs:15:6
[INFO] [stdout]    |
[INFO] [stdout] 14 | impl<T> List<T> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 15 |   fn new() -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 21 |   fn prepend(&self, value: T) -> List<T> {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |   fn tail(&self) -> List<T> {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 38 |   fn head(&self) -> Option<&T> {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `LinkedList` is never constructed
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 | pub struct LinkedList<T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `IntoIter` is never constructed
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:54:12
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub struct IntoIter<T>(LinkedList<T>);
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `Iter` is never constructed
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:72:12
[INFO] [stdout]    |
[INFO] [stdout] 72 | pub struct Iter<'a, T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `IterMut` is never constructed
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:98:12
[INFO] [stdout]    |
[INFO] [stdout] 98 | pub struct IterMut<'a, T> {
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `prepend`, `peek`, and `peek_mut` are never used
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:16:6
[INFO] [stdout]    |
[INFO] [stdout] 15 | impl<T> LinkedList<T> {
[INFO] [stdout]    | --------------------- associated items in this implementation
[INFO] [stdout] 16 |   fn new() -> Self {
[INFO] [stdout]    |      ^^^
[INFO] [stdout] ...
[INFO] [stdout] 20 |   fn prepend(&mut self, value: T) {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 40 |   fn peek(&self) -> Option<&T> {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 45 |   fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stdout]    |      ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:88:15
[INFO] [stdout]    |
[INFO] [stdout] 88 |   pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |               ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |               |
[INFO] [stdout]    |               the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 88 |   pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]    |                              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> linked-list/src/ok_linked_list.rs:114:19
[INFO] [stdout]     |
[INFO] [stdout] 114 |   pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                   ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                   |
[INFO] [stdout]     |                   the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 114 |   pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                         +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `linked-list` (lib) due to 7 previous errors; 9 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `length`
[INFO] [stdout]   --> stacks-queues/src/stacks.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let length = self.elements.len();
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_length`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> linked-list/src/ok_linked_list.rs:88:15
[INFO] [stdout]    |
[INFO] [stdout] 88 |   pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |               ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |               |
[INFO] [stdout]    |               the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 88 |   pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]    |                              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> linked-list/src/ok_linked_list.rs:114:19
[INFO] [stdout]     |
[INFO] [stdout] 114 |   pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                   ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                   |
[INFO] [stdout]     |                   the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 114 |   pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                         +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "96cffde7c99a6df0a913b7f08b9447a7febfddbdfc57cae424966a3904f3742d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "96cffde7c99a6df0a913b7f08b9447a7febfddbdfc57cae424966a3904f3742d", kill_on_drop: false }`
[INFO] [stdout] 96cffde7c99a6df0a913b7f08b9447a7febfddbdfc57cae424966a3904f3742d
