[INFO] fetching crate ringmaster 0.2.1...
[INFO] checking ringmaster-0.2.1 against master#c919f490bbcd2b29b74016101f7ec71aaa24bdbb for pr-79073
[INFO] extracting crate ringmaster 0.2.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate ringmaster 0.2.1 on toolchain c919f490bbcd2b29b74016101f7ec71aaa24bdbb
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c919f490bbcd2b29b74016101f7ec71aaa24bdbb" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ringmaster 0.2.1
[INFO] finished tweaking crates.io crate ringmaster 0.2.1
[INFO] tweaked toml for crates.io crate ringmaster 0.2.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c919f490bbcd2b29b74016101f7ec71aaa24bdbb" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c919f490bbcd2b29b74016101f7ec71aaa24bdbb" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+c919f490bbcd2b29b74016101f7ec71aaa24bdbb" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cc3f6608c7c1d241c3a99137ecb9e630532d8ecfedad09ff8991c42191627aa2
[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" "cc3f6608c7c1d241c3a99137ecb9e630532d8ecfedad09ff8991c42191627aa2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cc3f6608c7c1d241c3a99137ecb9e630532d8ecfedad09ff8991c42191627aa2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cc3f6608c7c1d241c3a99137ecb9e630532d8ecfedad09ff8991c42191627aa2", kill_on_drop: false }`
[INFO] [stdout] cc3f6608c7c1d241c3a99137ecb9e630532d8ecfedad09ff8991c42191627aa2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+c919f490bbcd2b29b74016101f7ec71aaa24bdbb" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 134fad8385a2be0e16e1a4c4bdff25514551ceeb42a203378dc2368fcbb0e2d4
[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" "134fad8385a2be0e16e1a4c4bdff25514551ceeb42a203378dc2368fcbb0e2d4", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]     Checking tokio v0.2.23
[INFO] [stderr]     Checking ringmaster v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variant is never constructed: `Root`
[INFO] [stdout]  --> src/lib.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 |     Root{ prev: usize, next: usize },
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Box`
[INFO] [stdout]  --> src/lib.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Box{ prev: usize, next: usize, item: T},
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `LIFO`
[INFO] [stdout]   --> src/lib.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     LIFO,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `buffer`
[INFO] [stdout]   --> src/lib.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 |     buffer: Mutex<Vec<RingBox<T>>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `mode`
[INFO] [stdout]   --> src/lib.rs:23:5
[INFO] [stdout]    |
[INFO] [stdout] 23 |     mode: Mode,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/lib.rs:28:8
[INFO] [stdout]    |
[INFO] [stdout] 28 |     fn new() -> Self {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `as_fifo`
[INFO] [stdout]   --> src/lib.rs:35:8
[INFO] [stdout]    |
[INFO] [stdout] 35 |     fn as_fifo(self) -> Self {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `as_lifo`
[INFO] [stdout]   --> src/lib.rs:42:8
[INFO] [stdout]    |
[INFO] [stdout] 42 |     fn as_lifo(self) -> Self {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `from`
[INFO] [stdout]   --> src/lib.rs:49:14
[INFO] [stdout]    |
[INFO] [stdout] 49 |     async fn from(vec: Vec<T>) -> Self {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `is_empty`
[INFO] [stdout]   --> src/lib.rs:57:14
[INFO] [stdout]    |
[INFO] [stdout] 57 |     async fn is_empty(&self) -> bool {
[INFO] [stdout]    |              ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push`
[INFO] [stdout]   --> src/lib.rs:61:14
[INFO] [stdout]    |
[INFO] [stdout] 61 |     async fn push(&self, item: T) {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `poll`
[INFO] [stdout]   --> src/lib.rs:84:14
[INFO] [stdout]    |
[INFO] [stdout] 84 |     async fn poll(&self) -> Option<T> {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `poll_with`
[INFO] [stdout]    --> src/lib.rs:150:14
[INFO] [stdout]     |
[INFO] [stdout] 150 |     async fn poll_with(&self, f: fn(&T) -> bool) -> Option<T> {
[INFO] [stdout]     |              ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `as_fifo`
[INFO] [stdout]   --> src/lib.rs:35:8
[INFO] [stdout]    |
[INFO] [stdout] 35 |     fn as_fifo(self) -> Self {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 6.56s
[INFO] running `Command { std: "docker" "inspect" "134fad8385a2be0e16e1a4c4bdff25514551ceeb42a203378dc2368fcbb0e2d4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "134fad8385a2be0e16e1a4c4bdff25514551ceeb42a203378dc2368fcbb0e2d4", kill_on_drop: false }`
[INFO] [stdout] 134fad8385a2be0e16e1a4c4bdff25514551ceeb42a203378dc2368fcbb0e2d4