[INFO] updating cached 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" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 255d021cb8214c82ca6d6002070da8d59b5c87a3
[INFO] testing mmmpa/learning_rust_data_structure against 1.45.2 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmmmpa%2Flearning_rust_data_structure" "/workspace/builds/worker-11/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mmmpa/learning_rust_data_structure on toolchain 1.45.2
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.45.2" "read-manifest" "--manifest-path" "Cargo.toml", 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-11/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: "/workspace/cargo-home/bin/cargo" "+1.45.2" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] fc29fbd5b9ee12491a088c0b738c23bfef81da3d59a408da00307711eb49007f
[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" "fc29fbd5b9ee12491a088c0b738c23bfef81da3d59a408da00307711eb49007f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fc29fbd5b9ee12491a088c0b738c23bfef81da3d59a408da00307711eb49007f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fc29fbd5b9ee12491a088c0b738c23bfef81da3d59a408da00307711eb49007f", kill_on_drop: false }`
[INFO] [stdout] fc29fbd5b9ee12491a088c0b738c23bfef81da3d59a408da00307711eb49007f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 9aef1a4ad003128376cbe39f2b6b755f70b2f809b5aa2daccc4d358cd7cffab4
[INFO] running `Command { std: "docker" "start" "-a" "9aef1a4ad003128376cbe39f2b6b755f70b2f809b5aa2daccc4d358cd7cffab4", 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: type alias is never used: `Traced`
[INFO] [stdout]  --> src/binary_search_tree.rs:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | type Traced<T> = Rc<RefCell<NodeBody<T>>>;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/binary_search_tree.rs:22:8
[INFO] [stdout]    |
[INFO] [stdout] 22 |     fn new(value: T) -> Node<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/binary_search_tree.rs:46:12
[INFO] [stdout]    |
[INFO] [stdout] 46 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert`
[INFO] [stdout]   --> src/binary_search_tree.rs:53:12
[INFO] [stdout]    |
[INFO] [stdout] 53 |     pub fn insert(&mut self, v: T) {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert_support`
[INFO] [stdout]   --> src/binary_search_tree.rs:59:8
[INFO] [stdout]    |
[INFO] [stdout] 59 |     fn insert_support(&mut self, root: Node<T>, v: T) -> Node<T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `trace`
[INFO] [stdout]   --> src/binary_search_tree.rs:76:8
[INFO] [stdout]    |
[INFO] [stdout] 76 |     fn trace(&self) -> Vec<Traced<T>> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `trace_support`
[INFO] [stdout]   --> src/binary_search_tree.rs:82:8
[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 is never used: `Traced`
[INFO] [stdout]  --> src/parental_binary_search_tree.rs:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | type Traced<T> = Rc<RefCell<NodeBody<T>>>;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `parent`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 17 |     parent: Node<T>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn new(value: T, parent: Node<T>) -> Node<T> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:47:12
[INFO] [stdout]    |
[INFO] [stdout] 47 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:54:12
[INFO] [stdout]    |
[INFO] [stdout] 54 |     pub fn insert(&mut self, v: T) {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert_support`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:60:8
[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] 
[INFO] [stdout] warning: associated function is never used: `trace`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:78:8
[INFO] [stdout]    |
[INFO] [stdout] 78 |     fn trace(&self) -> Vec<Traced<T>> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `trace_support`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:84:8
[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: 20 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.87s
[INFO] running `Command { std: "docker" "inspect" "9aef1a4ad003128376cbe39f2b6b755f70b2f809b5aa2daccc4d358cd7cffab4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9aef1a4ad003128376cbe39f2b6b755f70b2f809b5aa2daccc4d358cd7cffab4", kill_on_drop: false }`
[INFO] [stdout] 9aef1a4ad003128376cbe39f2b6b755f70b2f809b5aa2daccc4d358cd7cffab4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 24783bb1c9cce891798a6211ad1e0d9a2f1b25412d1c626d3b90878c3a804311
[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" "24783bb1c9cce891798a6211ad1e0d9a2f1b25412d1c626d3b90878c3a804311", 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/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]    = note: `#[warn(unused_mut)]` on by default
[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] 
[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 is never read: `parent`
[INFO] [stdout]   --> src/parental_binary_search_tree.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 17 |     parent: Node<T>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.12s
[INFO] running `Command { std: "docker" "inspect" "24783bb1c9cce891798a6211ad1e0d9a2f1b25412d1c626d3b90878c3a804311", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "24783bb1c9cce891798a6211ad1e0d9a2f1b25412d1c626d3b90878c3a804311", kill_on_drop: false }`
[INFO] [stdout] 24783bb1c9cce891798a6211ad1e0d9a2f1b25412d1c626d3b90878c3a804311
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "test" "--frozen", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 5d9ce3e24afe2f86ae1d5d62095bb254cc6c2f3ddefd14d22befedde05a8d6df
[INFO] running `Command { std: "docker" "start" "-a" "5d9ce3e24afe2f86ae1d5d62095bb254cc6c2f3ddefd14d22befedde05a8d6df", kill_on_drop: false }`
[INFO] [stderr] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stderr]  --> src/main.rs:1:5
[INFO] [stderr]   |
[INFO] [stderr] 1 | use core::borrow::BorrowMut;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stderr]  --> src/binary_search_tree.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use core::borrow::BorrowMut;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `core::borrow::BorrowMut`
[INFO] [stderr]  --> src/parental_binary_search_tree.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use core::borrow::BorrowMut;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:40:9
[INFO] [stderr]    |
[INFO] [stderr] 40 |     let mut raw_box = Rc::new(Test { value: None });
[INFO] [stderr]    |         ----^^^^^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/binary_search_tree.rs:62:18
[INFO] [stderr]    |
[INFO] [stderr] 62 |             Some(mut node) => {
[INFO] [stderr]    |                  ----^^^^
[INFO] [stderr]    |                  |
[INFO] [stderr]    |                  help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/parental_binary_search_tree.rs:63:18
[INFO] [stderr]    |
[INFO] [stderr] 63 |             Some(mut node) => {
[INFO] [stderr]    |                  ----^^^^
[INFO] [stderr]    |                  |
[INFO] [stderr]    |                  help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `parent`
[INFO] [stderr]   --> src/parental_binary_search_tree.rs:17:5
[INFO] [stderr]    |
[INFO] [stderr] 17 |     parent: Node<T>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 7 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.05s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/trees-1dc54319cb00eabd
[INFO] [stdout] 
[INFO] [stdout] running 4 tests
[INFO] [stdout] test test_rc ... ok
[INFO] [stdout] test test_box ... ok
[INFO] [stdout] test parental_binary_search_tree::test_insert ... ok
[INFO] [stdout] test binary_search_tree::test_insert ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 4 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "5d9ce3e24afe2f86ae1d5d62095bb254cc6c2f3ddefd14d22befedde05a8d6df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5d9ce3e24afe2f86ae1d5d62095bb254cc6c2f3ddefd14d22befedde05a8d6df", kill_on_drop: false }`
[INFO] [stdout] 5d9ce3e24afe2f86ae1d5d62095bb254cc6c2f3ddefd14d22befedde05a8d6df