[INFO] cloning repository https://github.com/gdt050579/double_linked_list_test-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/gdt050579/double_linked_list_test-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgdt050579%2Fdouble_linked_list_test-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgdt050579%2Fdouble_linked_list_test-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 97d92d40cd947dcc62a10371450b610bec746642
[INFO] checking gdt050579/double_linked_list_test-rs against master#1f12b9b0fdbe735968ac002792a720f0ba4faca6 for crater-rollup-uwu
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgdt050579%2Fdouble_linked_list_test-rs" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/gdt050579/double_linked_list_test-rs on toolchain 1f12b9b0fdbe735968ac002792a720f0ba4faca6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/gdt050579/double_linked_list_test-rs
[INFO] finished tweaking git repo https://github.com/gdt050579/double_linked_list_test-rs
[INFO] tweaked toml for git repo https://github.com/gdt050579/double_linked_list_test-rs written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/gdt050579/double_linked_list_test-rs 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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded stats_alloc v0.1.10
[INFO] [stderr]   Downloaded ascii_table v4.0.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a2d2348101947feb6140c10e3a9ec06821b2e3f89c5d5c978af3f5b3aa44967e
[INFO] running `Command { std: "docker" "start" "-a" "a2d2348101947feb6140c10e3a9ec06821b2e3f89c5d5c978af3f5b3aa44967e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a2d2348101947feb6140c10e3a9ec06821b2e3f89c5d5c978af3f5b3aa44967e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a2d2348101947feb6140c10e3a9ec06821b2e3f89c5d5c978af3f5b3aa44967e", kill_on_drop: false }`
[INFO] [stdout] a2d2348101947feb6140c10e3a9ec06821b2e3f89c5d5c978af3f5b3aa44967e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4d1660dd6b8a6cc4cf463358f875ec10c3f22ce52924fc23ee4146ed9a64e735
[INFO] running `Command { std: "docker" "start" "-a" "4d1660dd6b8a6cc4cf463358f875ec10c3f22ce52924fc23ee4146ed9a64e735", kill_on_drop: false }`
[INFO] [stderr]    Compiling libm v0.2.7
[INFO] [stderr]    Compiling slotmap v1.0.6
[INFO] [stderr]     Checking ascii_table v4.0.2
[INFO] [stderr]     Checking stats_alloc v0.1.10
[INFO] [stderr]     Checking humansize v2.1.3
[INFO] [stderr]     Checking double_linked_list_test-rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]   --> src/solutions/handle_impl.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 21 | pub struct Node {
[INFO] [stdout]    |            ---- field in this struct
[INFO] [stdout] 22 |     pub next: Handle,
[INFO] [stdout] 23 |     pub prec: Handle,
[INFO] [stdout]    |         ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]  --> src/solutions/index_impl.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub struct Node {
[INFO] [stdout]   |            ---- field in this struct
[INFO] [stdout] 2 |     pub next: usize,
[INFO] [stdout] 3 |     pub prec: usize,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]  --> src/solutions/rc_impl.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub struct Node {
[INFO] [stdout]   |            ---- field in this struct
[INFO] [stdout] 7 |     pub next: Option<Rc<RefCell<Node>>>,
[INFO] [stdout] 8 |     pub prec: Option<Weak<RefCell<Node>>>,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]   --> src/solutions/handle_impl.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 21 | pub struct Node {
[INFO] [stdout]    |            ---- field in this struct
[INFO] [stdout] 22 |     pub next: Handle,
[INFO] [stdout] 23 |     pub prec: Handle,
[INFO] [stdout]    |         ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]  --> src/solutions/index_impl.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub struct Node {
[INFO] [stdout]   |            ---- field in this struct
[INFO] [stdout] 2 |     pub next: usize,
[INFO] [stdout] 3 |     pub prec: usize,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `prec` is never read
[INFO] [stdout]  --> src/solutions/rc_impl.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub struct Node {
[INFO] [stdout]   |            ---- field in this struct
[INFO] [stdout] 7 |     pub next: Option<Rc<RefCell<Node>>>,
[INFO] [stdout] 8 |     pub prec: Option<Weak<RefCell<Node>>>,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.54s
[INFO] running `Command { std: "docker" "inspect" "4d1660dd6b8a6cc4cf463358f875ec10c3f22ce52924fc23ee4146ed9a64e735", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d1660dd6b8a6cc4cf463358f875ec10c3f22ce52924fc23ee4146ed9a64e735", kill_on_drop: false }`
[INFO] [stdout] 4d1660dd6b8a6cc4cf463358f875ec10c3f22ce52924fc23ee4146ed9a64e735