[INFO] cloning repository https://github.com/ctangam/linked-list
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ctangam/linked-list" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fctangam%2Flinked-list", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fctangam%2Flinked-list'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] eca75403606423ddd445aeef83e65ba3cd971dab
[INFO] checking ctangam/linked-list/eca75403606423ddd445aeef83e65ba3cd971dab against master#ab869e094a907cc5d19b4080f22eccaf347f1f95 for pr-129604
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fctangam%2Flinked-list" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ctangam/linked-list on toolchain ab869e094a907cc5d19b4080f22eccaf347f1f95
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ab869e094a907cc5d19b4080f22eccaf347f1f95" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ctangam/linked-list
[INFO] finished tweaking git repo https://github.com/ctangam/linked-list
[INFO] tweaked toml for git repo https://github.com/ctangam/linked-list written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/ctangam/linked-list already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ab869e094a907cc5d19b4080f22eccaf347f1f95" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+ab869e094a907cc5d19b4080f22eccaf347f1f95" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f724704d353786423f936c268f635298d288d7f89685b03e4150d41917f69a33
[INFO] running `Command { std: "docker" "start" "-a" "f724704d353786423f936c268f635298d288d7f89685b03e4150d41917f69a33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f724704d353786423f936c268f635298d288d7f89685b03e4150d41917f69a33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f724704d353786423f936c268f635298d288d7f89685b03e4150d41917f69a33", kill_on_drop: false }`
[INFO] [stdout] f724704d353786423f936c268f635298d288d7f89685b03e4150d41917f69a33
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "RUSTDOCFLAGS=--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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+ab869e094a907cc5d19b4080f22eccaf347f1f95" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f7e175830a58596c1e1de1126ccacfe7802d340a778dfb5ed191a3dda33c1eba
[INFO] running `Command { std: "docker" "start" "-a" "f7e175830a58596c1e1de1126ccacfe7802d340a778dfb5ed191a3dda33c1eba", kill_on_drop: false }`
[INFO] [stderr]     Checking lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/fourth.rs:44:24
[INFO] [stdout]    |
[INFO] [stdout] 44 | pub struct Iter<'a, T>(Option<Ref<'a, Node<T>>>);
[INFO] [stdout]    |            ----        ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |            |
[INFO] [stdout]    |            field in this struct
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider removing this field
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/silly1.rs:9:8
[INFO] [stdout]   |
[INFO] [stdout] 8 | impl<T> List<T> {
[INFO] [stdout]   | --------------- associated function in this implementation
[INFO] [stdout] 9 |     fn new() -> Self {
[INFO] [stdout]   |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/fourth.rs:44:24
[INFO] [stdout]    |
[INFO] [stdout] 44 | pub struct Iter<'a, T>(Option<Ref<'a, Node<T>>>);
[INFO] [stdout]    |            ----        ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |            |
[INFO] [stdout]    |            field in this struct
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider removing this field
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.58s
[INFO] running `Command { std: "docker" "inspect" "f7e175830a58596c1e1de1126ccacfe7802d340a778dfb5ed191a3dda33c1eba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f7e175830a58596c1e1de1126ccacfe7802d340a778dfb5ed191a3dda33c1eba", kill_on_drop: false }`
[INFO] [stdout] f7e175830a58596c1e1de1126ccacfe7802d340a778dfb5ed191a3dda33c1eba