[INFO] cloning repository https://github.com/leviathan88/safe_linked_lists_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/leviathan88/safe_linked_lists_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleviathan88%2Fsafe_linked_lists_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleviathan88%2Fsafe_linked_lists_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e4ba717536e07f5a946d94325cd53edd6273138b
[INFO] checking leviathan88/safe_linked_lists_rust against master#5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleviathan88%2Fsafe_linked_lists_rust" "/workspace/builds/worker-5/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/leviathan88/safe_linked_lists_rust on toolchain 5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/leviathan88/safe_linked_lists_rust
[INFO] finished tweaking git repo https://github.com/leviathan88/safe_linked_lists_rust
[INFO] tweaked toml for git repo https://github.com/leviathan88/safe_linked_lists_rust written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate git repo https://github.com/leviathan88/safe_linked_lists_rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b570a889afb1c1f41e3dc5500f7aebe39f8d0323fc31b0da97a0730edfdbf044
[INFO] running `Command { std: "docker" "start" "-a" "b570a889afb1c1f41e3dc5500f7aebe39f8d0323fc31b0da97a0730edfdbf044", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b570a889afb1c1f41e3dc5500f7aebe39f8d0323fc31b0da97a0730edfdbf044", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b570a889afb1c1f41e3dc5500f7aebe39f8d0323fc31b0da97a0730edfdbf044", kill_on_drop: false }`
[INFO] [stdout] b570a889afb1c1f41e3dc5500f7aebe39f8d0323fc31b0da97a0730edfdbf044
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9633ce5acf588c40f90a9c1224b80cc17664fad524f4fbb7c57f2b854be635cb
[INFO] running `Command { std: "docker" "start" "-a" "9633ce5acf588c40f90a9c1224b80cc17664fad524f4fbb7c57f2b854be635cb", kill_on_drop: false }`
[INFO] [stderr]     Checking linky_lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::cell::RefCell`
[INFO] [stdout]  --> src/lists/mod.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::cell::RefCell;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/lists/node.rs:70:9
[INFO] [stdout]    |
[INFO] [stdout] 70 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/lists/mod.rs:141:9
[INFO] [stdout]     |
[INFO] [stdout] 141 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new_empty`
[INFO] [stdout]   --> src/lists/mod.rs:18:12
[INFO] [stdout]    |
[INFO] [stdout] 18 |     pub fn new_empty() -> Self {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.33s
[INFO] running `Command { std: "docker" "inspect" "9633ce5acf588c40f90a9c1224b80cc17664fad524f4fbb7c57f2b854be635cb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9633ce5acf588c40f90a9c1224b80cc17664fad524f4fbb7c57f2b854be635cb", kill_on_drop: false }`
[INFO] [stdout] 9633ce5acf588c40f90a9c1224b80cc17664fad524f4fbb7c57f2b854be635cb