[INFO] cloning repository https://github.com/ParkinWu/search_tree
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ParkinWu/search_tree" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FParkinWu%2Fsearch_tree", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FParkinWu%2Fsearch_tree'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1150f31d3a8e45ad85e0cf6389803ddb6d371521
[INFO] checking ParkinWu/search_tree against master#936f2600b6c903b04387f74ed5cbce88bb06d243 for pr-91141
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FParkinWu%2Fsearch_tree" "/workspace/builds/worker-106/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-106/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ParkinWu/search_tree on toolchain 936f2600b6c903b04387f74ed5cbce88bb06d243
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ParkinWu/search_tree
[INFO] finished tweaking git repo https://github.com/ParkinWu/search_tree
[INFO] tweaked toml for git repo https://github.com/ParkinWu/search_tree written to /workspace/builds/worker-106/source/Cargo.toml
[INFO] crate git repo https://github.com/ParkinWu/search_tree already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded libc v0.2.15
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-106/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-106/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0299d27bb9f204885242426a2f8cfc04e8cd59afedbee8a2a586b537dc9decac
[INFO] running `Command { std: "docker" "start" "-a" "0299d27bb9f204885242426a2f8cfc04e8cd59afedbee8a2a586b537dc9decac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0299d27bb9f204885242426a2f8cfc04e8cd59afedbee8a2a586b537dc9decac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0299d27bb9f204885242426a2f8cfc04e8cd59afedbee8a2a586b537dc9decac", kill_on_drop: false }`
[INFO] [stdout] 0299d27bb9f204885242426a2f8cfc04e8cd59afedbee8a2a586b537dc9decac
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-106/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-106/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7c74c70707e19e37ef26d85bc95aa8135bbc6ce7492d207895f5b736ba8823f8
[INFO] running `Command { std: "docker" "start" "-a" "7c74c70707e19e37ef26d85bc95aa8135bbc6ce7492d207895f5b736ba8823f8", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]     Checking winapi v0.2.8
[INFO] [stderr]     Checking libc v0.2.15
[INFO] [stderr]    Compiling kernel32-sys v0.2.2
[INFO] [stderr]     Checking time v0.1.35
[INFO] [stderr]     Checking binary_tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Formatter`
[INFO] [stdout]  --> src/main.rs:4:24
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::{ Debug, Formatter};
[INFO] [stdout]   |                        ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Formatter`
[INFO] [stdout]  --> src/main.rs:4:24
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::{ Debug, Formatter};
[INFO] [stdout]   |                        ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `take_next`
[INFO] [stdout]   --> src/main.rs:58:8
[INFO] [stdout]    |
[INFO] [stdout] 58 |     fn take_next(&mut self) -> Option<Box<Self>> {
[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: `pop_back`
[INFO] [stdout]   --> src/main.rs:90:8
[INFO] [stdout]    |
[INFO] [stdout] 90 |     fn pop_back(&mut self) -> Option<T> {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_front`
[INFO] [stdout]    --> src/main.rs:103:8
[INFO] [stdout]     |
[INFO] [stdout] 103 |     fn push_front(&mut self, elem: T) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `pop_front`
[INFO] [stdout]    --> src/main.rs:113:8
[INFO] [stdout]     |
[INFO] [stdout] 113 |     fn pop_front(&mut self) -> Option<T> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]    --> src/main.rs:127:8
[INFO] [stdout]     |
[INFO] [stdout] 127 |     fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `tail`
[INFO] [stdout]    --> src/main.rs:161:5
[INFO] [stdout]     |
[INFO] [stdout] 161 |     tail: &'a Raw<T>,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `tail`
[INFO] [stdout]    --> src/main.rs:183:5
[INFO] [stdout]     |
[INFO] [stdout] 183 |     tail: Raw<T>,
[INFO] [stdout]     |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]    --> src/main.rs:127:8
[INFO] [stdout]     |
[INFO] [stdout] 127 |     fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `tail`
[INFO] [stdout]    --> src/main.rs:161:5
[INFO] [stdout]     |
[INFO] [stdout] 161 |     tail: &'a Raw<T>,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `tail`
[INFO] [stdout]    --> src/main.rs:183:5
[INFO] [stdout]     |
[INFO] [stdout] 183 |     tail: Raw<T>,
[INFO] [stdout]     |     ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 23.09s
[INFO] running `Command { std: "docker" "inspect" "7c74c70707e19e37ef26d85bc95aa8135bbc6ce7492d207895f5b736ba8823f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7c74c70707e19e37ef26d85bc95aa8135bbc6ce7492d207895f5b736ba8823f8", kill_on_drop: false }`
[INFO] [stdout] 7c74c70707e19e37ef26d85bc95aa8135bbc6ce7492d207895f5b736ba8823f8