[INFO] fetching crate thread_timer 0.3.0...
[INFO] checking thread_timer-0.3.0 against master#cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c for pr-143170
[INFO] extracting crate thread_timer 0.3.0 into /workspace/builds/worker-4-tc1/source
[INFO] started tweaking crates.io crate thread_timer 0.3.0
[INFO] finished tweaking crates.io crate thread_timer 0.3.0
[INFO] tweaked toml for crates.io crate thread_timer 0.3.0 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate thread_timer 0.3.0 on toolchain cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b99506a6917791247796d34aa71bb546c874a44f50211aa18d29169260556b57
[INFO] running `Command { std: "docker" "start" "-a" "b99506a6917791247796d34aa71bb546c874a44f50211aa18d29169260556b57", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b99506a6917791247796d34aa71bb546c874a44f50211aa18d29169260556b57", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b99506a6917791247796d34aa71bb546c874a44f50211aa18d29169260556b57", kill_on_drop: false }`
[INFO] [stdout] b99506a6917791247796d34aa71bb546c874a44f50211aa18d29169260556b57
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+cf38b8e663f15db10ce49d7bbce02c99fc3dbc0c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5b91ca71f83d74835e258131cd7d772748ee2c0e25633339a35834c3ae4a84cf
[INFO] running `Command { std: "docker" "start" "-a" "5b91ca71f83d74835e258131cd7d772748ee2c0e25633339a35834c3ae4a84cf", kill_on_drop: false }`
[INFO] [stderr]     Checking thread_timer v0.3.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]    --> src/lib.rs:240:13
[INFO] [stdout]     |
[INFO] [stdout] 240 |         let _ = is_waiting_condvar
[INFO] [stdout]     |             ^ this lock is not assigned to a binding and is immediately dropped
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[deny(let_underscore_lock)]` on by default
[INFO] [stdout] help: consider binding to an unused variable to avoid immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 240 |         let _unused = is_waiting_condvar
[INFO] [stdout]     |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 240 ~         drop(is_waiting_condvar
[INFO] [stdout] 241 |           .wait_while(is_waiting_lock.lock().unwrap(), |&mut is_waiting| {
[INFO] [stdout] 242 |             is_waiting
[INFO] [stdout] 243 |           })
[INFO] [stdout] 244 ~           .unwrap());
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `thread_timer` (lib test) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error: non-binding let on a synchronization lock
[INFO] [stdout]    --> src/lib.rs:240:13
[INFO] [stdout]     |
[INFO] [stdout] 240 |         let _ = is_waiting_condvar
[INFO] [stdout]     |             ^ this lock is not assigned to a binding and is immediately dropped
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[deny(let_underscore_lock)]` on by default
[INFO] [stdout] help: consider binding to an unused variable to avoid immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 240 |         let _unused = is_waiting_condvar
[INFO] [stdout]     |              ++++++
[INFO] [stdout] help: consider immediately dropping the value
[INFO] [stdout]     |
[INFO] [stdout] 240 ~         drop(is_waiting_condvar
[INFO] [stdout] 241 |           .wait_while(is_waiting_lock.lock().unwrap(), |&mut is_waiting| {
[INFO] [stdout] 242 |             is_waiting
[INFO] [stdout] 243 |           })
[INFO] [stdout] 244 ~           .unwrap());
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `thread_timer` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "5b91ca71f83d74835e258131cd7d772748ee2c0e25633339a35834c3ae4a84cf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b91ca71f83d74835e258131cd7d772748ee2c0e25633339a35834c3ae4a84cf", kill_on_drop: false }`
[INFO] [stdout] 5b91ca71f83d74835e258131cd7d772748ee2c0e25633339a35834c3ae4a84cf