[INFO] cloning repository https://github.com/sunnywhy/rust-thread-pool
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sunnywhy/rust-thread-pool" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsunnywhy%2Frust-thread-pool", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsunnywhy%2Frust-thread-pool'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6227f5fded0d0cecad295c6151b1fb82c4c45acf
[INFO] checking sunnywhy/rust-thread-pool against master#a5f164faad4a2fed606b8160fd7ecd2d5cbba381 for pr-84920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsunnywhy%2Frust-thread-pool" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sunnywhy/rust-thread-pool on toolchain a5f164faad4a2fed606b8160fd7ecd2d5cbba381
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sunnywhy/rust-thread-pool
[INFO] finished tweaking git repo https://github.com/sunnywhy/rust-thread-pool
[INFO] tweaked toml for git repo https://github.com/sunnywhy/rust-thread-pool written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/sunnywhy/rust-thread-pool already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7ef3f8185b0d2ce3bd4278be632b2322c2d088e8b53df3bff33336f714352cbc
[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" "7ef3f8185b0d2ce3bd4278be632b2322c2d088e8b53df3bff33336f714352cbc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7ef3f8185b0d2ce3bd4278be632b2322c2d088e8b53df3bff33336f714352cbc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7ef3f8185b0d2ce3bd4278be632b2322c2d088e8b53df3bff33336f714352cbc", kill_on_drop: false }`
[INFO] [stdout] 7ef3f8185b0d2ce3bd4278be632b2322c2d088e8b53df3bff33336f714352cbc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e4526ac327d4383930ea95a8fe4c85c5b480e70263434164dc32a0023d87c475
[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" "e4526ac327d4383930ea95a8fe4c85c5b480e70263434164dc32a0023d87c475", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking rust_thread_pool v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `MutexGuard` that must be used
[INFO] [stdout]   --> src/main.rs:38:13
[INFO] [stdout]    |
[INFO] [stdout] 38 |             self.empty_trigger.lock().expect("Unable to notify all joining threads");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if unused the Mutex will immediately unlock
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `MutexGuard` that must be used
[INFO] [stdout]   --> src/main.rs:38:13
[INFO] [stdout]    |
[INFO] [stdout] 38 |             self.empty_trigger.lock().expect("Unable to notify all joining threads");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if unused the Mutex will immediately unlock
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.04s
[INFO] running `Command { std: "docker" "inspect" "e4526ac327d4383930ea95a8fe4c85c5b480e70263434164dc32a0023d87c475", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e4526ac327d4383930ea95a8fe4c85c5b480e70263434164dc32a0023d87c475", kill_on_drop: false }`
[INFO] [stdout] e4526ac327d4383930ea95a8fe4c85c5b480e70263434164dc32a0023d87c475