[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#4fb54ed484e2239a3e9eff3be17df00d2a162be3 for pr-73345
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleviathan88%2Fsafe_linked_lists_rust" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/leviathan88/safe_linked_lists_rust on toolchain 4fb54ed484e2239a3e9eff3be17df00d2a162be3
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4fb54ed484e2239a3e9eff3be17df00d2a162be3" "read-manifest" "--manifest-path" "Cargo.toml", 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-7/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" "+4fb54ed484e2239a3e9eff3be17df00d2a162be3" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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@sha256:6c9ffe128752d56c8d75334ed354142a5229917ed99767f56566dd8e857ad726" "/opt/rustwide/cargo-home/bin/cargo" "+4fb54ed484e2239a3e9eff3be17df00d2a162be3" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e9316fe2967bf23f37597c30da0bc0cc12be2269d841e27b2c22c460249acd59
[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" "e9316fe2967bf23f37597c30da0bc0cc12be2269d841e27b2c22c460249acd59", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e9316fe2967bf23f37597c30da0bc0cc12be2269d841e27b2c22c460249acd59", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e9316fe2967bf23f37597c30da0bc0cc12be2269d841e27b2c22c460249acd59", kill_on_drop: false }`
[INFO] [stdout] e9316fe2967bf23f37597c30da0bc0cc12be2269d841e27b2c22c460249acd59
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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=forbid" "-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@sha256:6c9ffe128752d56c8d75334ed354142a5229917ed99767f56566dd8e857ad726" "/opt/rustwide/cargo-home/bin/cargo" "+4fb54ed484e2239a3e9eff3be17df00d2a162be3" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 62ecd59aa2c4ac4f5b99b9e0761ff72cb168c28a622c3091985cdc436116fd6a
[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" "62ecd59aa2c4ac4f5b99b9e0761ff72cb168c28a622c3091985cdc436116fd6a", kill_on_drop: false }`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[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 0.51s
[INFO] running `Command { std: "docker" "inspect" "62ecd59aa2c4ac4f5b99b9e0761ff72cb168c28a622c3091985cdc436116fd6a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "62ecd59aa2c4ac4f5b99b9e0761ff72cb168c28a622c3091985cdc436116fd6a", kill_on_drop: false }`
[INFO] [stdout] 62ecd59aa2c4ac4f5b99b9e0761ff72cb168c28a622c3091985cdc436116fd6a