[INFO] cloning repository https://github.com/mmmpa/learning_rust_data_structure
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mmmpa/learning_rust_data_structure" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmmmpa%2Flearning_rust_data_structure", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmmmpa%2Flearning_rust_data_structure'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 255d021cb8214c82ca6d6002070da8d59b5c87a3
[INFO] building mmmpa/learning_rust_data_structure against master#9bd71afb90c2a6e0348cdd4a2b10a3bf39908f19 for pr-117684
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmmmpa%2Flearning_rust_data_structure" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mmmpa/learning_rust_data_structure on toolchain 9bd71afb90c2a6e0348cdd4a2b10a3bf39908f19
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9bd71afb90c2a6e0348cdd4a2b10a3bf39908f19" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mmmpa/learning_rust_data_structure
[INFO] finished tweaking git repo https://github.com/mmmpa/learning_rust_data_structure
[INFO] tweaked toml for git repo https://github.com/mmmpa/learning_rust_data_structure written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/mmmpa/learning_rust_data_structure 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" "+9bd71afb90c2a6e0348cdd4a2b10a3bf39908f19" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] building mmmpa/learning_rust_data_structure against try#53e03135c36e913ff664ce8329041b7e3c2fd358 for pr-117684
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmmmpa%2Flearning_rust_data_structure" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mmmpa/learning_rust_data_structure on toolchain 53e03135c36e913ff664ce8329041b7e3c2fd358
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+53e03135c36e913ff664ce8329041b7e3c2fd358" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mmmpa/learning_rust_data_structure
[INFO] finished tweaking git repo https://github.com/mmmpa/learning_rust_data_structure
[INFO] tweaked toml for git repo https://github.com/mmmpa/learning_rust_data_structure written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/mmmpa/learning_rust_data_structure 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" "+53e03135c36e913ff664ce8329041b7e3c2fd358" "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-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+53e03135c36e913ff664ce8329041b7e3c2fd358" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ff4113c929e70a790d86ed4b52cf6a46a28a706390d5bba7b9c9cb08af837bab
[INFO] running `Command { std: "docker" "start" "-a" "ff4113c929e70a790d86ed4b52cf6a46a28a706390d5bba7b9c9cb08af837bab", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ff4113c929e70a790d86ed4b52cf6a46a28a706390d5bba7b9c9cb08af837bab", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ff4113c929e70a790d86ed4b52cf6a46a28a706390d5bba7b9c9cb08af837bab", kill_on_drop: false }`
[INFO] [stdout] ff4113c929e70a790d86ed4b52cf6a46a28a706390d5bba7b9c9cb08af837bab
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+53e03135c36e913ff664ce8329041b7e3c2fd358" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8a0e1c67e910259f831399f988a84b4a7cd7dd17374f36caae6a39c7ff79b6d9
[INFO] running `Command { std: "docker" "start" "-a" "8a0e1c67e910259f831399f988a84b4a7cd7dd17374f36caae6a39c7ff79b6d9", kill_on_drop: false }`
[INFO] [stderr]    Compiling trees v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/binary_search_tree.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/parental_binary_search_tree.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/binary_search_tree.rs:62:18
[INFO] [stdout]    |
[INFO] [stdout] 62 |             Some(mut node) => {
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:63:18
[INFO] [stdout]    |
[INFO] [stdout] 63 |             Some(mut node) => {
[INFO] [stdout]    |                  ----^^^^
[INFO] [stdout]    |                  |
[INFO] [stdout]    |                  help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `boxer` is never read
[INFO] [stdout]   --> src/main.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | struct TestContainer {
[INFO] [stdout]    |        ------------- field in this struct
[INFO] [stdout] 13 |     boxer: Box<Test>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `TestContainer` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `rcer` is never read
[INFO] [stdout]   --> src/main.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct TestRc {
[INFO] [stdout]    |        ------ field in this struct
[INFO] [stdout] 18 |     rcer: Rc<Test>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `TestRc` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `value` is never read
[INFO] [stdout]   --> src/main.rs:23:5
[INFO] [stdout]    |
[INFO] [stdout] 22 | struct Test {
[INFO] [stdout]    |        ---- field in this struct
[INFO] [stdout] 23 |     value: Option<usize>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `Test` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `Traced` is never used
[INFO] [stdout]  --> src/binary_search_tree.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 7 | type Traced<T> = Rc<RefCell<NodeBody<T>>>;
[INFO] [stdout]   |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `root` and `length` are never read
[INFO] [stdout]   --> src/binary_search_tree.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct BinarySearchTree<T: Ord + Debug> {
[INFO] [stdout]    |        ---------------- fields in this struct
[INFO] [stdout] 11 |     root: Node<T>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 12 |     length: u32,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `BinarySearchTree` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/binary_search_tree.rs:22:8
[INFO] [stdout]    |
[INFO] [stdout] 21 | impl<T: Ord + Debug> NodeBody<T> {
[INFO] [stdout]    | -------------------------------- associated function in this implementation
[INFO] [stdout] 22 |     fn new(value: T) -> Node<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `insert`, `insert_support`, `trace`, and `trace_support` are never used
[INFO] [stdout]   --> src/binary_search_tree.rs:46:12
[INFO] [stdout]    |
[INFO] [stdout] 45 | impl<T: Ord + Debug> BinarySearchTree<T> {
[INFO] [stdout]    | ---------------------------------------- associated items in this implementation
[INFO] [stdout] 46 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 53 |     pub fn insert(&mut self, v: T) {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 59 |     fn insert_support(&mut self, root: Node<T>, v: T) -> Node<T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 76 |     fn trace(&self) -> Vec<Traced<T>> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 82 |     fn trace_support(&self, root: &Node<T>, result: &mut Vec<Traced<T>>) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `Traced` is never used
[INFO] [stdout]  --> src/parental_binary_search_tree.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 7 | type Traced<T> = Rc<RefCell<NodeBody<T>>>;
[INFO] [stdout]   |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `root` and `length` are never read
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct BinarySearchTree<T: Ord + Debug> {
[INFO] [stdout]    |        ---------------- fields in this struct
[INFO] [stdout] 11 |     root: Node<T>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 12 |     length: u32,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `BinarySearchTree` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `parent` is never read
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 15 | struct NodeBody<T: Ord + Debug> {
[INFO] [stdout]    |        -------- field in this struct
[INFO] [stdout] 16 |     value: T,
[INFO] [stdout] 17 |     parent: Node<T>,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 22 | impl<T: Ord + Debug> NodeBody<T> {
[INFO] [stdout]    | -------------------------------- associated function in this implementation
[INFO] [stdout] 23 |     fn new(value: T, parent: Node<T>) -> Node<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `insert`, `insert_support`, `trace`, and `trace_support` are never used
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:47:12
[INFO] [stdout]    |
[INFO] [stdout] 46 | impl<T: Ord + Debug> BinarySearchTree<T> {
[INFO] [stdout]    | ---------------------------------------- associated items in this implementation
[INFO] [stdout] 47 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 54 |     pub fn insert(&mut self, v: T) {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 60 |     fn insert_support(&mut self, root: Node<T>, v: T, p: Node<T>) -> Node<T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 78 |     fn trace(&self) -> Vec<Traced<T>> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 84 |     fn trace_support(&self, root: &Node<T>, result: &mut Vec<Traced<T>>) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 17 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.18s
[INFO] running `Command { std: "docker" "inspect" "8a0e1c67e910259f831399f988a84b4a7cd7dd17374f36caae6a39c7ff79b6d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8a0e1c67e910259f831399f988a84b4a7cd7dd17374f36caae6a39c7ff79b6d9", kill_on_drop: false }`
[INFO] [stdout] 8a0e1c67e910259f831399f988a84b4a7cd7dd17374f36caae6a39c7ff79b6d9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+53e03135c36e913ff664ce8329041b7e3c2fd358" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5e77b18b83f8315cd476787499e6789648a063768b47de0fd270de61e95536f8
[INFO] running `Command { std: "docker" "start" "-a" "5e77b18b83f8315cd476787499e6789648a063768b47de0fd270de61e95536f8", kill_on_drop: false }`
[INFO] [stderr]    Compiling trees v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/binary_search_tree.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stdout]  --> src/parental_binary_search_tree.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use core::borrow::BorrowMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/binary_search_tree.rs:62:18
[INFO] [stdout]    |
[INFO] [stdout] 62 |             Some(mut node) => {
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:63:18
[INFO] [stdout]    |
[INFO] [stdout] 63 |             Some(mut node) => {
[INFO] [stdout]    |                  ----^^^^
[INFO] [stdout]    |                  |
[INFO] [stdout]    |                  help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let mut raw_box = Rc::new(Test { value: None });
[INFO] [stdout]    |         ----^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `rcer` is never read
[INFO] [stdout]   --> src/main.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct TestRc {
[INFO] [stdout]    |        ------ field in this struct
[INFO] [stdout] 18 |     rcer: Rc<Test>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `TestRc` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `parent` is never read
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 15 | struct NodeBody<T: Ord + Debug> {
[INFO] [stdout]    |        -------- field in this struct
[INFO] [stdout] 16 |     value: T,
[INFO] [stdout] 17 |     parent: Node<T>,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.46s
[INFO] running `Command { std: "docker" "inspect" "5e77b18b83f8315cd476787499e6789648a063768b47de0fd270de61e95536f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5e77b18b83f8315cd476787499e6789648a063768b47de0fd270de61e95536f8", kill_on_drop: false }`
[INFO] [stdout] 5e77b18b83f8315cd476787499e6789648a063768b47de0fd270de61e95536f8