[INFO] cloning repository https://github.com/christiansakai/linked_list_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/christiansakai/linked_list_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchristiansakai%2Flinked_list_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchristiansakai%2Flinked_list_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b59f6d038c7a3a9c7cfb4a83a0103de5a7b175ce
[INFO] checking christiansakai/linked_list_rust against try#8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8 for pr-82565
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchristiansakai%2Flinked_list_rust" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/christiansakai/linked_list_rust on toolchain 8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/christiansakai/linked_list_rust
[INFO] finished tweaking git repo https://github.com/christiansakai/linked_list_rust
[INFO] tweaked toml for git repo https://github.com/christiansakai/linked_list_rust written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/christiansakai/linked_list_rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e1a2eab3866202fcf12b78c720fbe624fb5ee11f8ede8354a12f2abcf8da6100
[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" "e1a2eab3866202fcf12b78c720fbe624fb5ee11f8ede8354a12f2abcf8da6100", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e1a2eab3866202fcf12b78c720fbe624fb5ee11f8ede8354a12f2abcf8da6100", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e1a2eab3866202fcf12b78c720fbe624fb5ee11f8ede8354a12f2abcf8da6100", kill_on_drop: false }`
[INFO] [stdout] e1a2eab3866202fcf12b78c720fbe624fb5ee11f8ede8354a12f2abcf8da6100
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "check" "--frozen" "--all" "--all-targets" "--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] 6673f3b4f9b6ee52b1ad2f85611706ae124c61ec04e2b224bf28a0be48145f58
[INFO] running `Command { std: "docker" "start" "-a" "6673f3b4f9b6ee52b1ad2f85611706ae124c61ec04e2b224bf28a0be48145f58", kill_on_drop: false }`
[INFO] [stderr]     Checking linked_list_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/first.rs:75:9
[INFO] [stdout]    |
[INFO] [stdout] 75 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `elem`
[INFO] [stdout]   --> src/fourth.rs:51:33
[INFO] [stdout]    |
[INFO] [stdout] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stdout]    |                                 ^^^^ help: if this is intentional, prefix it with an underscore: `_elem`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `elem`
[INFO] [stdout]   --> src/fourth.rs:51:33
[INFO] [stdout]    |
[INFO] [stdout] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stdout]    |                                 ^^^^ help: if this is intentional, prefix it with an underscore: `_elem`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.18s
[INFO] running `Command { std: "docker" "inspect" "6673f3b4f9b6ee52b1ad2f85611706ae124c61ec04e2b224bf28a0be48145f58", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6673f3b4f9b6ee52b1ad2f85611706ae124c61ec04e2b224bf28a0be48145f58", kill_on_drop: false }`
[INFO] [stdout] 6673f3b4f9b6ee52b1ad2f85611706ae124c61ec04e2b224bf28a0be48145f58