[INFO] fetching crate subway 0.1.2...
[INFO] checking subway-0.1.2 against master#836c31742687ba4e2f857b5b698e1e9e6b67619c for pr-81789
[INFO] extracting crate subway 0.1.2 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate subway 0.1.2 on toolchain 836c31742687ba4e2f857b5b698e1e9e6b67619c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate subway 0.1.2
[INFO] finished tweaking crates.io crate subway 0.1.2
[INFO] tweaked toml for crates.io crate subway 0.1.2 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 238092b1fb60a517893dceb8d7a9854ea7b2b107fc56bc27cce869da7428cdfe
[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" "238092b1fb60a517893dceb8d7a9854ea7b2b107fc56bc27cce869da7428cdfe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "238092b1fb60a517893dceb8d7a9854ea7b2b107fc56bc27cce869da7428cdfe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "238092b1fb60a517893dceb8d7a9854ea7b2b107fc56bc27cce869da7428cdfe", kill_on_drop: false }`
[INFO] [stdout] 238092b1fb60a517893dceb8d7a9854ea7b2b107fc56bc27cce869da7428cdfe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+836c31742687ba4e2f857b5b698e1e9e6b67619c" "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] 957ca2a8cfe75f11688a831a3be9555553a5061e2d4bbd9d3793387033ee63a5
[INFO] running `Command { std: "docker" "start" "-a" "957ca2a8cfe75f11688a831a3be9555553a5061e2d4bbd9d3793387033ee63a5", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking subway v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `up`
[INFO] [stdout]   --> src/skiplist.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     up: WeakLink<K, V>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `print`
[INFO] [stdout]    --> src/skiplist.rs:574:8
[INFO] [stdout]     |
[INFO] [stdout] 574 |     fn print(&self) {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `up`
[INFO] [stdout]   --> src/skiplist.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     up: WeakLink<K, V>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `print`
[INFO] [stdout]    --> src/skiplist.rs:574:8
[INFO] [stdout]     |
[INFO] [stdout] 574 |     fn print(&self) {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.16s
[INFO] running `Command { std: "docker" "inspect" "957ca2a8cfe75f11688a831a3be9555553a5061e2d4bbd9d3793387033ee63a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "957ca2a8cfe75f11688a831a3be9555553a5061e2d4bbd9d3793387033ee63a5", kill_on_drop: false }`
[INFO] [stdout] 957ca2a8cfe75f11688a831a3be9555553a5061e2d4bbd9d3793387033ee63a5