[INFO] fetching crate polonius-engine 0.12.1...
[INFO] checking polonius-engine-0.12.1 against try#6f8a6450478f69b8510c8976ab6c2a70b3b0e47c for pr-84920
[INFO] extracting crate polonius-engine 0.12.1 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate polonius-engine 0.12.1 on toolchain 6f8a6450478f69b8510c8976ab6c2a70b3b0e47c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f8a6450478f69b8510c8976ab6c2a70b3b0e47c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate polonius-engine 0.12.1
[INFO] finished tweaking crates.io crate polonius-engine 0.12.1
[INFO] tweaked toml for crates.io crate polonius-engine 0.12.1 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f8a6450478f69b8510c8976ab6c2a70b3b0e47c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f8a6450478f69b8510c8976ab6c2a70b3b0e47c" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded datafrog v2.0.1
[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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+6f8a6450478f69b8510c8976ab6c2a70b3b0e47c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8053cf8a347ac653e217474fdf70ba67c41701c1571aa6e62de91f5b213ae4ab
[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" "8053cf8a347ac653e217474fdf70ba67c41701c1571aa6e62de91f5b213ae4ab", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8053cf8a347ac653e217474fdf70ba67c41701c1571aa6e62de91f5b213ae4ab", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8053cf8a347ac653e217474fdf70ba67c41701c1571aa6e62de91f5b213ae4ab", kill_on_drop: false }`
[INFO] [stdout] 8053cf8a347ac653e217474fdf70ba67c41701c1571aa6e62de91f5b213ae4ab
[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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+6f8a6450478f69b8510c8976ab6c2a70b3b0e47c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 52a329fa43ecd0f9eff6c6a80fbd9129e996e348a970ce4b97e505002abe06d2
[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" "52a329fa43ecd0f9eff6c6a80fbd9129e996e348a970ce4b97e505002abe06d2", kill_on_drop: false }`
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking datafrog v2.0.1
[INFO] [stderr]     Checking rustc-hash v1.1.0
[INFO] [stderr]     Checking polonius-engine v0.12.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `potential_errors`
[INFO] [stdout]    --> src/output/mod.rs:139:5
[INFO] [stdout]     |
[INFO] [stdout] 139 |     potential_errors: Option<FxHashSet<T::Loan>>,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `potential_errors`
[INFO] [stdout]    --> src/output/mod.rs:139:5
[INFO] [stdout]     |
[INFO] [stdout] 139 |     potential_errors: Option<FxHashSet<T::Loan>>,
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.43s
[INFO] running `Command { std: "docker" "inspect" "52a329fa43ecd0f9eff6c6a80fbd9129e996e348a970ce4b97e505002abe06d2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52a329fa43ecd0f9eff6c6a80fbd9129e996e348a970ce4b97e505002abe06d2", kill_on_drop: false }`
[INFO] [stdout] 52a329fa43ecd0f9eff6c6a80fbd9129e996e348a970ce4b97e505002abe06d2