[INFO] cloning repository https://github.com/sdttttt/RBTree-Rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sdttttt/RBTree-Rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsdttttt%2FRBTree-Rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsdttttt%2FRBTree-Rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ca02c1d8b84f8c3c6e3f70a65bbfc6ee81e7be2e
[INFO] testing sdttttt/RBTree-Rust against master#432e145bd5a974c5b6f4dd9b352891bd7502b69d for pr-87041
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsdttttt%2FRBTree-Rust" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sdttttt/RBTree-Rust on toolchain 432e145bd5a974c5b6f4dd9b352891bd7502b69d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sdttttt/RBTree-Rust
[INFO] finished tweaking git repo https://github.com/sdttttt/RBTree-Rust
[INFO] tweaked toml for git repo https://github.com/sdttttt/RBTree-Rust written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/sdttttt/RBTree-Rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "metadata" "--no-deps" "--format-version=1", 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] 536009df2172b22ccd358be651642c59dfd86e4e59bd7e102da8fd19a421176f
[INFO] running `Command { std: "docker" "start" "-a" "536009df2172b22ccd358be651642c59dfd86e4e59bd7e102da8fd19a421176f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "536009df2172b22ccd358be651642c59dfd86e4e59bd7e102da8fd19a421176f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "536009df2172b22ccd358be651642c59dfd86e4e59bd7e102da8fd19a421176f", kill_on_drop: false }`
[INFO] [stdout] 536009df2172b22ccd358be651642c59dfd86e4e59bd7e102da8fd19a421176f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fb02110fab6f7b20f88ed2bcd2427054fd0930eed620c1706a0e676a26785bc2
[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" "fb02110fab6f7b20f88ed2bcd2427054fd0930eed620c1706a0e676a26785bc2", kill_on_drop: false }`
[INFO] [stderr]    Compiling red-black-tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable `node_p` is assigned to, but never used
[INFO] [stdout]   --> src/main.rs:43:17
[INFO] [stdout]    |
[INFO] [stdout] 43 |         let mut node_p: SchrodingerNode<K, V>;
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout]    = note: consider using `_node_p` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `node_p` is never read
[INFO] [stdout]   --> src/main.rs:46:13
[INFO] [stdout]    |
[INFO] [stdout] 46 |             node_p = node.clone();
[INFO] [stdout]    |             ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/main.rs:41:26
[INFO] [stdout]    |
[INFO] [stdout] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stdout]    |                          ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_node`
[INFO] [stdout]    --> src/main.rs:104:13
[INFO] [stdout]     |
[INFO] [stdout] 104 |         let new_node = Some(Box::new(Node::new(key, value)));
[INFO] [stdout]     |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |         let mut node: SchrodingerNode<K, V>;
[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: variant is never constructed: `BLACK`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     BLACK,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Tree`
[INFO] [stdout]   --> src/main.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct Tree<K, V> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `value`
[INFO] [stdout]   --> src/main.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     value: V,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `color`
[INFO] [stdout]   --> src/main.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 |     color: Color,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/main.rs:37:8
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn new() -> Tree<K, V> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert`
[INFO] [stdout]   --> src/main.rs:41:8
[INFO] [stdout]    |
[INFO] [stdout] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.66s
[INFO] running `Command { std: "docker" "inspect" "fb02110fab6f7b20f88ed2bcd2427054fd0930eed620c1706a0e676a26785bc2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fb02110fab6f7b20f88ed2bcd2427054fd0930eed620c1706a0e676a26785bc2", kill_on_drop: false }`
[INFO] [stdout] fb02110fab6f7b20f88ed2bcd2427054fd0930eed620c1706a0e676a26785bc2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1667adbf79091510a82d2830ca3137abbdc5155bc7c5c897e88dbd04d0bef4e6
[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" "1667adbf79091510a82d2830ca3137abbdc5155bc7c5c897e88dbd04d0bef4e6", kill_on_drop: false }`
[INFO] [stderr]    Compiling red-black-tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable `node_p` is assigned to, but never used
[INFO] [stdout]   --> src/main.rs:43:17
[INFO] [stdout]    |
[INFO] [stdout] 43 |         let mut node_p: SchrodingerNode<K, V>;
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout]    = note: consider using `_node_p` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `node_p` is never read
[INFO] [stdout]   --> src/main.rs:46:13
[INFO] [stdout]    |
[INFO] [stdout] 46 |             node_p = node.clone();
[INFO] [stdout]    |             ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/main.rs:41:26
[INFO] [stdout]    |
[INFO] [stdout] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stdout]    |                          ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `new_node`
[INFO] [stdout]    --> src/main.rs:104:13
[INFO] [stdout]     |
[INFO] [stdout] 104 |         let new_node = Some(Box::new(Node::new(key, value)));
[INFO] [stdout]     |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |         let mut node: SchrodingerNode<K, V>;
[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: variant is never constructed: `BLACK`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     BLACK,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Tree`
[INFO] [stdout]   --> src/main.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct Tree<K, V> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `value`
[INFO] [stdout]   --> src/main.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     value: V,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `color`
[INFO] [stdout]   --> src/main.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 |     color: Color,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/main.rs:37:8
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn new() -> Tree<K, V> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `insert`
[INFO] [stdout]   --> src/main.rs:41:8
[INFO] [stdout]    |
[INFO] [stdout] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.73s
[INFO] running `Command { std: "docker" "inspect" "1667adbf79091510a82d2830ca3137abbdc5155bc7c5c897e88dbd04d0bef4e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1667adbf79091510a82d2830ca3137abbdc5155bc7c5c897e88dbd04d0bef4e6", kill_on_drop: false }`
[INFO] [stdout] 1667adbf79091510a82d2830ca3137abbdc5155bc7c5c897e88dbd04d0bef4e6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+432e145bd5a974c5b6f4dd9b352891bd7502b69d" "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] 239e8a357b03a8a81e0a2f853cac4970d70038de9b66235a4a41374ee38da86a
[INFO] running `Command { std: "docker" "start" "-a" "239e8a357b03a8a81e0a2f853cac4970d70038de9b66235a4a41374ee38da86a", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: variable `node_p` is assigned to, but never used
[INFO] [stdout] running 0 tests
[INFO] [stderr]   --> src/main.rs:43:17
[INFO] [stdout] 
[INFO] [stderr]    |
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 43 |         let mut node_p: SchrodingerNode<K, V>;
[INFO] [stdout] 
[INFO] [stderr]    |                 ^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr]    = note: consider using `_node_p` instead
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `node_p` is never read
[INFO] [stderr]   --> src/main.rs:46:13
[INFO] [stderr]    |
[INFO] [stderr] 46 |             node_p = node.clone();
[INFO] [stderr]    |             ^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `v`
[INFO] [stderr]   --> src/main.rs:41:26
[INFO] [stderr]    |
[INFO] [stderr] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stderr]    |                          ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `new_node`
[INFO] [stderr]    --> src/main.rs:104:13
[INFO] [stderr]     |
[INFO] [stderr] 104 |         let new_node = Some(Box::new(Node::new(key, value)));
[INFO] [stderr]     |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_node`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:42:13
[INFO] [stderr]    |
[INFO] [stderr] 42 |         let mut node: SchrodingerNode<K, V>;
[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: variant is never constructed: `BLACK`
[INFO] [stderr]   --> src/main.rs:10:5
[INFO] [stderr]    |
[INFO] [stderr] 10 |     BLACK,
[INFO] [stderr]    |     ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `Tree`
[INFO] [stderr]   --> src/main.rs:13:8
[INFO] [stderr]    |
[INFO] [stderr] 13 | struct Tree<K, V> {
[INFO] [stderr]    |        ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `value`
[INFO] [stderr]   --> src/main.rs:19:5
[INFO] [stderr]    |
[INFO] [stderr] 19 |     value: V,
[INFO] [stderr]    |     ^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `color`
[INFO] [stderr]   --> src/main.rs:20:5
[INFO] [stderr]    |
[INFO] [stderr] 20 |     color: Color,
[INFO] [stderr]    |     ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `new`
[INFO] [stderr]   --> src/main.rs:37:8
[INFO] [stderr]    |
[INFO] [stderr] 37 |     fn new() -> Tree<K, V> {
[INFO] [stderr]    |        ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `insert`
[INFO] [stderr]   --> src/main.rs:41:8
[INFO] [stderr]    |
[INFO] [stderr] 41 |     fn insert(&self,k:K, v: V) {
[INFO] [stderr]    |        ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: 11 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.03s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/red_black_tree-8e91caac5f1c6913)
[INFO] running `Command { std: "docker" "inspect" "239e8a357b03a8a81e0a2f853cac4970d70038de9b66235a4a41374ee38da86a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "239e8a357b03a8a81e0a2f853cac4970d70038de9b66235a4a41374ee38da86a", kill_on_drop: false }`
[INFO] [stdout] 239e8a357b03a8a81e0a2f853cac4970d70038de9b66235a4a41374ee38da86a