[INFO] cloning repository https://github.com/francis8991/clrs-rust-challenge
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/francis8991/clrs-rust-challenge" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffrancis8991%2Fclrs-rust-challenge", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffrancis8991%2Fclrs-rust-challenge'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d31d15c46244b202c3bff4215df99623bd8f838f
[INFO] testing francis8991/clrs-rust-challenge against 1.99.0-beta.8 for beta-1.100-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffrancis8991%2Fclrs-rust-challenge" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/francis8991/clrs-rust-challenge
[INFO] finished tweaking git repo https://github.com/francis8991/clrs-rust-challenge
[INFO] tweaked toml for git repo https://github.com/francis8991/clrs-rust-challenge written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/francis8991/clrs-rust-challenge on toolchain 1.99.0-beta.8
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.99.0-beta.8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/francis8991/clrs-rust-challenge 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" "+1.99.0-beta.8" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3111399a4047eeb3a02b7a90e478d715f38a8c6669b5c4b49d30a17385265909" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51
[INFO] running `Command { std: "docker" "start" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.8" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling CLRS-rust-challenge v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: struct `List` is never constructed
[INFO] [stdout]  --> src/double_list.rs:4:12
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub struct List<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: type alias `Link` is never used
[INFO] [stdout]  --> src/double_list.rs:9:6
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Link<T> = Option<Rc<RefCell<Node<T>>>>;
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]   --> src/double_list.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Node<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/double_list.rs:18:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | impl<T> Node<T> {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] 18 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: multiple associated items are never used
[INFO] [stdout]    --> src/double_list.rs:28:12
[INFO] [stdout]     |
[INFO] [stdout]  27 | impl<T> List<T> {
[INFO] [stdout]     | --------------- associated items in this implementation
[INFO] [stdout]  28 |     pub fn new() -> Self {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] ...
[INFO] [stdout]  35 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stdout]     |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  50 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  65 |     pub fn pop_back(&mut self) -> Option<T> {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  80 |     pub fn pop_front(&mut self) -> Option<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  95 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 101 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 119 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `IntoIter` is never constructed
[INFO] [stdout]    --> src/double_list.rs:130:12
[INFO] [stdout]     |
[INFO] [stdout] 130 | pub struct IntoIter<T>(List<T>);
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate `CLRS_rust_challenge` should have a snake case name
[INFO] [stdout]   |
[INFO] [stdout]   = help: convert the identifier to snake case: `clrs_rust_challenge`
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/double_list.rs:95:23
[INFO] [stdout]    |
[INFO] [stdout] 95 |     pub fn peek_front(&self) -> Option<Ref<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] 95 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:101:22
[INFO] [stdout]     |
[INFO] [stdout] 101 |     pub fn peek_back(&self) -> Option<Ref<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] 101 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:107:26
[INFO] [stdout]     |
[INFO] [stdout] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<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] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:113:27
[INFO] [stdout]     |
[INFO] [stdout] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<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] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.38s
[INFO] running `Command { std: "docker" "inspect" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.8" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling CLRS-rust-challenge v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: struct `List` is never constructed
[INFO] [stdout]  --> src/double_list.rs:4:12
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub struct List<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: type alias `Link` is never used
[INFO] [stdout]  --> src/double_list.rs:9:6
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Link<T> = Option<Rc<RefCell<Node<T>>>>;
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]   --> src/double_list.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Node<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/double_list.rs:18:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | impl<T> Node<T> {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] 18 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: multiple associated items are never used
[INFO] [stdout]    --> src/double_list.rs:28:12
[INFO] [stdout]     |
[INFO] [stdout]  27 | impl<T> List<T> {
[INFO] [stdout]     | --------------- associated items in this implementation
[INFO] [stdout]  28 |     pub fn new() -> Self {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] ...
[INFO] [stdout]  35 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stdout]     |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  50 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  65 |     pub fn pop_back(&mut self) -> Option<T> {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  80 |     pub fn pop_front(&mut self) -> Option<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  95 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 101 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 119 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `IntoIter` is never constructed
[INFO] [stdout]    --> src/double_list.rs:130:12
[INFO] [stdout]     |
[INFO] [stdout] 130 | pub struct IntoIter<T>(List<T>);
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate `CLRS_rust_challenge` should have a snake case name
[INFO] [stdout]   |
[INFO] [stdout]   = help: convert the identifier to snake case: `clrs_rust_challenge`
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/double_list.rs:95:23
[INFO] [stdout]    |
[INFO] [stdout] 95 |     pub fn peek_front(&self) -> Option<Ref<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] 95 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:101:22
[INFO] [stdout]     |
[INFO] [stdout] 101 |     pub fn peek_back(&self) -> Option<Ref<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] 101 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:107:26
[INFO] [stdout]     |
[INFO] [stdout] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<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] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:113:27
[INFO] [stdout]     |
[INFO] [stdout] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<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] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/double_list.rs:95:23
[INFO] [stdout]    |
[INFO] [stdout] 95 |     pub fn peek_front(&self) -> Option<Ref<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] 95 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:101:22
[INFO] [stdout]     |
[INFO] [stdout] 101 |     pub fn peek_back(&self) -> Option<Ref<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] 101 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:107:26
[INFO] [stdout]     |
[INFO] [stdout] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<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] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/double_list.rs:113:27
[INFO] [stdout]     |
[INFO] [stdout] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<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] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.51s
[INFO] running `Command { std: "docker" "inspect" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.8" "test" "--frozen", kill_on_drop: false }`
[INFO] [stderr] warning: struct `List` is never constructed
[INFO] [stderr]  --> src/double_list.rs:4:12
[INFO] [stderr]   |
[INFO] [stderr] 4 | pub struct List<T> {
[INFO] [stderr]   |            ^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: type alias `Link` is never used
[INFO] [stderr]  --> src/double_list.rs:9:6
[INFO] [stderr]   |
[INFO] [stderr] 9 | type Link<T> = Option<Rc<RefCell<Node<T>>>>;
[INFO] [stderr]   |      ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct `Node` is never constructed
[INFO] [stderr]   --> src/double_list.rs:11:8
[INFO] [stderr]    |
[INFO] [stderr] 11 | struct Node<T> {
[INFO] [stderr]    |        ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function `new` is never used
[INFO] [stderr]   --> src/double_list.rs:18:8
[INFO] [stderr]    |
[INFO] [stderr] 17 | impl<T> Node<T> {
[INFO] [stderr]    | --------------- associated function in this implementation
[INFO] [stderr] 18 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stderr]    |        ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: multiple associated items are never used
[INFO] [stderr]    --> src/double_list.rs:28:12
[INFO] [stderr]     |
[INFO] [stderr]  27 | impl<T> List<T> {
[INFO] [stderr]     | --------------- associated items in this implementation
[INFO] [stderr]  28 |     pub fn new() -> Self {
[INFO] [stderr]     |            ^^^
[INFO] [stderr] ...
[INFO] [stderr]  35 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stderr]     |            ^^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr]  50 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stderr]     |            ^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr]  65 |     pub fn pop_back(&mut self) -> Option<T> {
[INFO] [stderr]     |            ^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr]  80 |     pub fn pop_front(&mut self) -> Option<T> {
[INFO] [stderr]     |            ^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr]  95 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |            ^^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 101 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |            ^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |            ^^^^^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |            ^^^^^^^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 119 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr]     |            ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct `IntoIter` is never constructed
[INFO] [stderr]    --> src/double_list.rs:130:12
[INFO] [stderr]     |
[INFO] [stderr] 130 | pub struct IntoIter<T>(List<T>);
[INFO] [stderr]     |            ^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: crate `CLRS_rust_challenge` should have a snake case name
[INFO] [stderr]   |
[INFO] [stderr]   = help: convert the identifier to snake case: `clrs_rust_challenge`
[INFO] [stderr]   = note: `#[warn(non_snake_case)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]   --> src/double_list.rs:95:23
[INFO] [stderr]    |
[INFO] [stderr] 95 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |                       ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stderr]    |                       |
[INFO] [stderr]    |                       the lifetime is elided here
[INFO] [stderr]    |
[INFO] [stderr]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]    |
[INFO] [stderr] 95 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]    |                                            +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/double_list.rs:101:22
[INFO] [stderr]     |
[INFO] [stderr] 101 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |                      ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                      |
[INFO] [stderr]     |                      the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 101 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]     |                                           +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/double_list.rs:107:26
[INFO] [stderr]     |
[INFO] [stderr] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                          ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                          |
[INFO] [stderr]     |                          the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 107 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                      +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/double_list.rs:113:27
[INFO] [stderr]     |
[INFO] [stderr] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                           ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                           |
[INFO] [stderr]     |                           the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 113 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                       +++
[INFO] [stderr] 
[INFO] [stderr] warning: `CLRS-rust-challenge` (lib) generated 11 warnings (run `cargo fix --lib -p CLRS-rust-challenge` to apply 4 suggestions)
[INFO] [stderr] warning: `CLRS-rust-challenge` (lib test) generated 4 warnings (4 duplicates)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/CLRS_rust_challenge-bc183ab91d4e2486)
[INFO] [stdout] 
[INFO] [stdout] running 3 tests
[INFO] [stdout] test double_list::test::basics ... ok
[INFO] [stdout] test double_list::test::into_iter ... ok
[INFO] [stdout] test double_list::test::peek ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]      Running unittests src/main.rs (/opt/rustwide/target/debug/deps/CLRS_rust_challenge-0a350bd47ac95636)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests CLRS_rust_challenge
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51", kill_on_drop: false }`
[INFO] [stdout] a16018c3dee27825bf8c915c09919c899fdcf2a83fb427d93f3005bc3d031b51
