[INFO] cloning repository https://github.com/DemonWav/idiots-delight
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/DemonWav/idiots-delight" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FDemonWav%2Fidiots-delight", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FDemonWav%2Fidiots-delight'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 71a339a925b32cdaaef5678a971f151c10d15e15
[INFO] checking DemonWav/idiots-delight against master#04ff05c9c0cfbca33115c5f1b8bb20a66a54b799 for pr-147834
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FDemonWav%2Fidiots-delight" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/DemonWav/idiots-delight
[INFO] finished tweaking git repo https://github.com/DemonWav/idiots-delight
[INFO] tweaked toml for git repo https://github.com/DemonWav/idiots-delight written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/DemonWav/idiots-delight on toolchain 04ff05c9c0cfbca33115c5f1b8bb20a66a54b799
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+04ff05c9c0cfbca33115c5f1b8bb20a66a54b799" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/DemonWav/idiots-delight 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" "+04ff05c9c0cfbca33115c5f1b8bb20a66a54b799" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded num_cpus v1.11.0
[INFO] [stderr]   Downloaded hermit-abi v0.1.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+04ff05c9c0cfbca33115c5f1b8bb20a66a54b799" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 67c0104e6b55ba1c69d81a155ff5f52846f1add52402a9ef7612dafe0d19090c
[INFO] running `Command { std: "docker" "start" "-a" "67c0104e6b55ba1c69d81a155ff5f52846f1add52402a9ef7612dafe0d19090c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "67c0104e6b55ba1c69d81a155ff5f52846f1add52402a9ef7612dafe0d19090c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "67c0104e6b55ba1c69d81a155ff5f52846f1add52402a9ef7612dafe0d19090c", kill_on_drop: false }`
[INFO] [stdout] 67c0104e6b55ba1c69d81a155ff5f52846f1add52402a9ef7612dafe0d19090c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+04ff05c9c0cfbca33115c5f1b8bb20a66a54b799" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ab668d360af630db46be51b02dcec4efe5ce57fa2e7c19ffee6ec06899a05b2b
[INFO] running `Command { std: "docker" "start" "-a" "ab668d360af630db46be51b02dcec4efe5ce57fa2e7c19ffee6ec06899a05b2b", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.65
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]     Checking nodrop v0.1.14
[INFO] [stderr]     Checking itoa v0.4.4
[INFO] [stderr]     Checking num-format v0.4.0
[INFO] [stderr]     Checking getrandom v0.1.13
[INFO] [stderr]     Checking num_cpus v1.11.0
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]     Checking idiots-delight v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]    --> src/main.rs:106:13
[INFO] [stdout]     |
[INFO] [stdout] 106 |         let _ = lock.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] 106 |         let _unused = lock.lock().unwrap();
[INFO] [stdout]     |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 106 -         let _ = lock.lock().unwrap();
[INFO] [stdout] 106 +         drop(lock.lock().unwrap());
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]    --> src/main.rs:106:13
[INFO] [stdout]     |
[INFO] [stdout] 106 |         let _ = lock.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] 106 |         let _unused = lock.lock().unwrap();
[INFO] [stdout]     |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 106 -         let _ = lock.lock().unwrap();
[INFO] [stdout] 106 +         drop(lock.lock().unwrap());
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `idiots-delight` (bin "idiots-delight" test) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: could not compile `idiots-delight` (bin "idiots-delight") due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "ab668d360af630db46be51b02dcec4efe5ce57fa2e7c19ffee6ec06899a05b2b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ab668d360af630db46be51b02dcec4efe5ce57fa2e7c19ffee6ec06899a05b2b", kill_on_drop: false }`
[INFO] [stdout] ab668d360af630db46be51b02dcec4efe5ce57fa2e7c19ffee6ec06899a05b2b
