[INFO] cloning repository https://github.com/martin-lukas/rust-playground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/martin-lukas/rust-playground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmartin-lukas%2Frust-playground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmartin-lukas%2Frust-playground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f9f5503315c058e4ca77bd8e70da4240cae73315
[INFO] checking martin-lukas/rust-playground against master#3cdcdaf31b45f8045164aae9604573d23091970b for pr-122267
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmartin-lukas%2Frust-playground" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/martin-lukas/rust-playground on toolchain 3cdcdaf31b45f8045164aae9604573d23091970b
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3cdcdaf31b45f8045164aae9604573d23091970b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/martin-lukas/rust-playground
[INFO] finished tweaking git repo https://github.com/martin-lukas/rust-playground
[INFO] tweaked toml for git repo https://github.com/martin-lukas/rust-playground written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/martin-lukas/rust-playground 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" "+3cdcdaf31b45f8045164aae9604573d23091970b" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking martin-lukas/rust-playground against try#05804f728f276cf7ecedbf71c814df440d37f293 for pr-122267
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmartin-lukas%2Frust-playground" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/martin-lukas/rust-playground on toolchain 05804f728f276cf7ecedbf71c814df440d37f293
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+05804f728f276cf7ecedbf71c814df440d37f293" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/martin-lukas/rust-playground
[INFO] finished tweaking git repo https://github.com/martin-lukas/rust-playground
[INFO] tweaked toml for git repo https://github.com/martin-lukas/rust-playground written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/martin-lukas/rust-playground 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" "+05804f728f276cf7ecedbf71c814df440d37f293" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+05804f728f276cf7ecedbf71c814df440d37f293" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d505c98845a8e6be2fe7e57f68bc9dcd15ee9f2d2872511da6f2629a9099737b
[INFO] running `Command { std: "docker" "start" "-a" "d505c98845a8e6be2fe7e57f68bc9dcd15ee9f2d2872511da6f2629a9099737b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d505c98845a8e6be2fe7e57f68bc9dcd15ee9f2d2872511da6f2629a9099737b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d505c98845a8e6be2fe7e57f68bc9dcd15ee9f2d2872511da6f2629a9099737b", kill_on_drop: false }`
[INFO] [stdout] d505c98845a8e6be2fe7e57f68bc9dcd15ee9f2d2872511da6f2629a9099737b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+05804f728f276cf7ecedbf71c814df440d37f293" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7472ab617353b966793a4b23571debd188dd6c98e8a6ddd5c56be24b51fb40d6
[INFO] running `Command { std: "docker" "start" "-a" "7472ab617353b966793a4b23571debd188dd6c98e8a6ddd5c56be24b51fb40d6", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-playground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function `print_out_items` is never used
[INFO] [stdout]  --> src/print_items_twice.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn print_out_items(items: &Vec<u32>) {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `last_foo`
[INFO] [stdout]  --> src/keep_ref_to_popped_arr_elem.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     let last_foo = vector.last();
[INFO] [stdout]   |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_last_foo`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` 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` profile [unoptimized + debuginfo] target(s) in 0.17s
[INFO] running `Command { std: "docker" "inspect" "7472ab617353b966793a4b23571debd188dd6c98e8a6ddd5c56be24b51fb40d6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7472ab617353b966793a4b23571debd188dd6c98e8a6ddd5c56be24b51fb40d6", kill_on_drop: false }`
[INFO] [stdout] 7472ab617353b966793a4b23571debd188dd6c98e8a6ddd5c56be24b51fb40d6