[INFO] cloning repository https://github.com/CampoDiFiori/doubly-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/CampoDiFiori/doubly-linked-list-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCampoDiFiori%2Fdoubly-linked-list-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCampoDiFiori%2Fdoubly-linked-list-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7cde3edee757ac05d06308fd48385783740f79f6
[INFO] checking CampoDiFiori/doubly-linked-list-rust against try#9c1dcf141bc0875407c4eb36972857bd3db713e2 for pr-81863
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FCampoDiFiori%2Fdoubly-linked-list-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/CampoDiFiori/doubly-linked-list-rust on toolchain 9c1dcf141bc0875407c4eb36972857bd3db713e2
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9c1dcf141bc0875407c4eb36972857bd3db713e2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/CampoDiFiori/doubly-linked-list-rust
[INFO] finished tweaking git repo https://github.com/CampoDiFiori/doubly-linked-list-rust
[INFO] tweaked toml for git repo https://github.com/CampoDiFiori/doubly-linked-list-rust written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/CampoDiFiori/doubly-linked-list-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9c1dcf141bc0875407c4eb36972857bd3db713e2" "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" "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:ce6408862c0f4858e6cd2b85b2cf085ff7d0d6323904d0a94b71664a228554ab" "/opt/rustwide/cargo-home/bin/cargo" "+9c1dcf141bc0875407c4eb36972857bd3db713e2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6eba5d6de31bec7169a14422b4a9f63f6d983c465b09dec16148ecd0cc2b0354
[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" "6eba5d6de31bec7169a14422b4a9f63f6d983c465b09dec16148ecd0cc2b0354", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6eba5d6de31bec7169a14422b4a9f63f6d983c465b09dec16148ecd0cc2b0354", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6eba5d6de31bec7169a14422b4a9f63f6d983c465b09dec16148ecd0cc2b0354", kill_on_drop: false }`
[INFO] [stdout] 6eba5d6de31bec7169a14422b4a9f63f6d983c465b09dec16148ecd0cc2b0354
[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" "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:ce6408862c0f4858e6cd2b85b2cf085ff7d0d6323904d0a94b71664a228554ab" "/opt/rustwide/cargo-home/bin/cargo" "+9c1dcf141bc0875407c4eb36972857bd3db713e2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3debd5c6cc7cef6bd2882f3557e8b814fe1c6d6d81a35d81e2776a982d4d619b
[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" "3debd5c6cc7cef6bd2882f3557e8b814fe1c6d6d81a35d81e2776a982d4d619b", kill_on_drop: false }`
[INFO] [stderr]     Checking doubly-linked-list-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `prev`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     prev: Option<NodePtr<T>>,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `prev`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     prev: Option<NodePtr<T>>,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.33s
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "3debd5c6cc7cef6bd2882f3557e8b814fe1c6d6d81a35d81e2776a982d4d619b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3debd5c6cc7cef6bd2882f3557e8b814fe1c6d6d81a35d81e2776a982d4d619b", kill_on_drop: false }`
[INFO] [stdout] 3debd5c6cc7cef6bd2882f3557e8b814fe1c6d6d81a35d81e2776a982d4d619b