[INFO] cloning repository https://github.com/pirocks/mutex-bench
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/pirocks/mutex-bench" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpirocks%2Fmutex-bench", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpirocks%2Fmutex-bench'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7b3faee5ea3035711f58c4dcd0105445739978f5
[INFO] checking pirocks/mutex-bench against 36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6 for pr-160581
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpirocks%2Fmutex-bench" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/pirocks/mutex-bench
[INFO] finished tweaking git repo https://github.com/pirocks/mutex-bench
[INFO] tweaked toml for git repo https://github.com/pirocks/mutex-bench written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/pirocks/mutex-bench on toolchain 36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/pirocks/mutex-bench 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" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking pirocks/mutex-bench against 36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6 for pr-160581
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpirocks%2Fmutex-bench" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/pirocks/mutex-bench
[INFO] finished tweaking git repo https://github.com/pirocks/mutex-bench
[INFO] tweaked toml for git repo https://github.com/pirocks/mutex-bench written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/pirocks/mutex-bench on toolchain 36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/pirocks/mutex-bench 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" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded tsc v0.1.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:8683fc1fc2eb5c9ac98e0d076ab094b2ffac7f99da555d2b6a2e27f346de2ec7" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0
[INFO] running `Command { std: "docker" "start" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0" "/opt/rustwide/cargo-home/bin/cargo" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-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" "-w" "/opt/rustwide/workdir" "--user" "0:0" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0" "/opt/rustwide/cargo-home/bin/cargo" "+36e0a7eac2392bdd51fab6e7ff1d8c0e42d33bf6" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling tsc v0.1.0
[INFO] [stderr]     Checking either v1.6.1
[INFO] [stderr]     Checking itertools v0.10.3
[INFO] [stderr]     Checking mutex-bench v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error: could not compile `mutex-bench` (bin "mutex-bench") due to 1 previous error
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]   --> src/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let _ = uncondented_mutex.lock().unwrap();
[INFO] [stdout]    |             ^ this lock is not assigned to a binding and is immediately dropped
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[deny(let_underscore_lock)]` (part of `#[deny(let_underscore)]`) on by default
[INFO] [stdout] help: consider binding to an unused variable to avoid immediately dropping the value
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let _unused = uncondented_mutex.lock().unwrap();
[INFO] [stdout]    |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]    |
[INFO] [stdout] 11 -         let _ = uncondented_mutex.lock().unwrap();
[INFO] [stdout] 11 +         drop(uncondented_mutex.lock().unwrap());
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]   --> src/main.rs:11:13
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let _ = uncondented_mutex.lock().unwrap();
[INFO] [stdout]    |             ^ this lock is not assigned to a binding and is immediately dropped
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[deny(let_underscore_lock)]` (part of `#[deny(let_underscore)]`) on by default
[INFO] [stdout] help: consider binding to an unused variable to avoid immediately dropping the value
[INFO] [stdout]    |
[INFO] [stdout] 11 |         let _unused = uncondented_mutex.lock().unwrap();
[INFO] [stdout]    |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]    |
[INFO] [stdout] 11 -         let _ = uncondented_mutex.lock().unwrap();
[INFO] [stdout] 11 +         drop(uncondented_mutex.lock().unwrap());
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `mutex-bench` (bin "mutex-bench" test) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0", kill_on_drop: false }`
[INFO] [stdout] c936224cf38eae4d0f8b3f0036747e295e94101d143bd5551bd8eb54a5a688c0
