[INFO] fetching crate maybe-single 0.12.0...
[INFO] checking maybe-single-0.12.0 against try#9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c for pr-79472
[INFO] extracting crate maybe-single 0.12.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate maybe-single 0.12.0 on toolchain 9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate maybe-single 0.12.0
[INFO] finished tweaking crates.io crate maybe-single 0.12.0
[INFO] tweaked toml for crates.io crate maybe-single 0.12.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "+9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 2be2b800ccb8bd8ae9ec9e32f97e5e5226f4ae64228d5195b86fecc296569af3
[INFO] running `Command { std: "docker" "start" "-a" "2be2b800ccb8bd8ae9ec9e32f97e5e5226f4ae64228d5195b86fecc296569af3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2be2b800ccb8bd8ae9ec9e32f97e5e5226f4ae64228d5195b86fecc296569af3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2be2b800ccb8bd8ae9ec9e32f97e5e5226f4ae64228d5195b86fecc296569af3", kill_on_drop: false }`
[INFO] [stdout] 2be2b800ccb8bd8ae9ec9e32f97e5e5226f4ae64228d5195b86fecc296569af3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "+9b49d8c6c904f63eb486fe51b14bbe0aa2feda4c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bdf9159333bf100210b5666c008c446bf8153b236f73b1b194b820421894580e
[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" "bdf9159333bf100210b5666c008c446bf8153b236f73b1b194b820421894580e", kill_on_drop: false }`
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.54
[INFO] [stderr]     Checking smallvec v1.5.1
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking once_cell v1.5.2
[INFO] [stderr]     Checking signal-hook-registry v1.2.2
[INFO] [stderr]     Checking net2 v0.2.36
[INFO] [stderr]     Checking getrandom v0.1.15
[INFO] [stderr]     Checking parking_lot_core v0.7.2
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking parking_lot v0.10.2
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking maybe-single v0.12.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::ops::Deref`
[INFO] [stdout]  --> src/nio.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ops::Deref;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `RwLockReadGuard`, `RwLockWriteGuard`
[INFO] [stdout]  --> src/nio.rs:6:34
[INFO] [stdout]   |
[INFO] [stdout] 6 | use parking_lot::{Mutex, RwLock, RwLockReadGuard, RwLockWriteGuard};
[INFO] [stdout]   |                                  ^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `read_lock`
[INFO] [stdout]   --> src/lib.rs:77:5
[INFO] [stdout]    |
[INFO] [stdout] 77 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `write_lock`
[INFO] [stdout]   --> src/lib.rs:78:5
[INFO] [stdout]    |
[INFO] [stdout] 78 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]     Checking tokio v0.2.23
[INFO] [stdout] warning: unused import: `std::ops::Deref`
[INFO] [stdout]  --> src/nio.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ops::Deref;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `RwLockReadGuard`, `RwLockWriteGuard`
[INFO] [stdout]  --> src/nio.rs:6:34
[INFO] [stdout]   |
[INFO] [stdout] 6 | use parking_lot::{Mutex, RwLock, RwLockReadGuard, RwLockWriteGuard};
[INFO] [stdout]   |                                  ^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Rng`, `thread_rng`
[INFO] [stdout]   --> src/nio.rs:87:16
[INFO] [stdout]    |
[INFO] [stdout] 87 |     use rand::{thread_rng, Rng};
[INFO] [stdout]    |                ^^^^^^^^^^  ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::sleep`
[INFO] [stdout]   --> src/nio.rs:88:9
[INFO] [stdout]    |
[INFO] [stdout] 88 |     use std::thread::sleep;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::time::Duration`
[INFO] [stdout]   --> src/nio.rs:89:9
[INFO] [stdout]    |
[INFO] [stdout] 89 |     use std::time::Duration;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `tokio::time::Instant`
[INFO] [stdout]   --> src/nio.rs:90:9
[INFO] [stdout]    |
[INFO] [stdout] 90 |     use tokio::time::Instant;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::future::Future`
[INFO] [stdout]    --> src/lib.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |     use std::future::Future;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::pin::Pin`
[INFO] [stdout]    --> src/lib.rs:120:9
[INFO] [stdout]     |
[INFO] [stdout] 120 |     use std::pin::Pin;
[INFO] [stdout]     |         ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `read_lock`
[INFO] [stdout]   --> src/lib.rs:77:5
[INFO] [stdout]    |
[INFO] [stdout] 77 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `write_lock`
[INFO] [stdout]   --> src/lib.rs:78:5
[INFO] [stdout]    |
[INFO] [stdout] 78 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 29.78s
[INFO] running `Command { std: "docker" "inspect" "bdf9159333bf100210b5666c008c446bf8153b236f73b1b194b820421894580e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bdf9159333bf100210b5666c008c446bf8153b236f73b1b194b820421894580e", kill_on_drop: false }`
[INFO] [stdout] bdf9159333bf100210b5666c008c446bf8153b236f73b1b194b820421894580e