[INFO] crate maybe-single 0.8.0-async-alpha.3 is already in cache
[INFO] checking maybe-single-0.8.0-async-alpha.3 against master#3dbade652ed8ebac70f903e01f51cd92c4e4302c for pr-69880
[INFO] extracting crate maybe-single 0.8.0-async-alpha.3 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate maybe-single 0.8.0-async-alpha.3 on toolchain 3dbade652ed8ebac70f903e01f51cd92c4e4302c
[INFO] running `"/workspace/cargo-home/bin/cargo" "+3dbade652ed8ebac70f903e01f51cd92c4e4302c" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate maybe-single 0.8.0-async-alpha.3
[INFO] finished tweaking crates.io crate maybe-single 0.8.0-async-alpha.3
[INFO] tweaked toml for crates.io crate maybe-single 0.8.0-async-alpha.3 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+3dbade652ed8ebac70f903e01f51cd92c4e4302c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+3dbade652ed8ebac70f903e01f51cd92c4e4302c" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+3dbade652ed8ebac70f903e01f51cd92c4e4302c" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3ed7956fd28910d0aea7b185342682851495cc14651fdd45298b006984083975
[INFO] running `"docker" "start" "-a" "3ed7956fd28910d0aea7b185342682851495cc14651fdd45298b006984083975"`
[INFO] [stderr]     Checking maybe-single v0.8.0-async-alpha.3 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking tokio v0.2.13
[INFO] [stderr]     Checking futures-util v0.3.4
[INFO] [stderr] warning: field is never read: `read_lock`
[INFO] [stderr]   --> src/nio.rs:85:5
[INFO] [stderr]    |
[INFO] [stderr] 85 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `write_lock`
[INFO] [stderr]   --> src/nio.rs:86:5
[INFO] [stderr]    |
[INFO] [stderr] 86 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `read_lock`
[INFO] [stderr]   --> src/lib.rs:75:5
[INFO] [stderr]    |
[INFO] [stderr] 75 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `write_lock`
[INFO] [stderr]   --> src/lib.rs:76:5
[INFO] [stderr]    |
[INFO] [stderr] 76 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Checking futures-executor v0.3.4
[INFO] [stderr]     Checking futures v0.3.4
[INFO] [stderr] warning: unused imports: `Rng`, `thread_rng`
[INFO] [stderr]    --> src/nio.rs:127:16
[INFO] [stderr]     |
[INFO] [stderr] 127 |     use rand::{thread_rng, Rng};
[INFO] [stderr]     |                ^^^^^^^^^^  ^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::thread::sleep`
[INFO] [stderr]    --> src/nio.rs:128:9
[INFO] [stderr]     |
[INFO] [stderr] 128 |     use std::thread::sleep;
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::time::Duration`
[INFO] [stderr]    --> src/nio.rs:129:9
[INFO] [stderr]     |
[INFO] [stderr] 129 |     use std::time::Duration;
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `t`
[INFO] [stderr]    --> src/nio.rs:137:27
[INFO] [stderr]     |
[INFO] [stderr] 137 |     fn need_send<T: Send>(t: T) {}
[INFO] [stderr]     |                           ^ help: consider prefixing with an underscore: `_t`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `t`
[INFO] [stderr]    --> src/nio.rs:138:27
[INFO] [stderr]     |
[INFO] [stderr] 138 |     fn need_sync<T: Sync>(t: T) {}
[INFO] [stderr]     |                           ^ help: consider prefixing with an underscore: `_t`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `maybe_clone`
[INFO] [stderr]    --> src/nio.rs:155:13
[INFO] [stderr]     |
[INFO] [stderr] 155 |         let maybe_clone = maybe.clone();
[INFO] [stderr]     |             ^^^^^^^^^^^ help: consider prefixing with an underscore: `_maybe_clone`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s`
[INFO] [stderr]    --> src/lib.rs:163:13
[INFO] [stderr]     |
[INFO] [stderr] 163 |         let s = String::new();
[INFO] [stderr]     |             ^ help: consider prefixing with an underscore: `_s`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `callback`
[INFO] [stderr]    --> src/lib.rs:161:34
[INFO] [stderr]     |
[INFO] [stderr] 161 |     pub fn call_async<'a, 'b, F>(callback: fn(&'a str) -> F)
[INFO] [stderr]     |                                  ^^^^^^^^ help: consider prefixing with an underscore: `_callback`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `value_ref`
[INFO] [stderr]    --> src/lib.rs:176:17
[INFO] [stderr]     |
[INFO] [stderr] 176 |             let value_ref = value;
[INFO] [stderr]     |                 ^^^^^^^^^ help: consider prefixing with an underscore: `_value_ref`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `value_ref`
[INFO] [stderr]    --> src/lib.rs:182:17
[INFO] [stderr]     |
[INFO] [stderr] 182 |             let value_ref = value;
[INFO] [stderr]     |                 ^^^^^^^^^ help: consider prefixing with an underscore: `_value_ref`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `read_lock`
[INFO] [stderr]   --> src/nio.rs:85:5
[INFO] [stderr]    |
[INFO] [stderr] 85 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `write_lock`
[INFO] [stderr]   --> src/nio.rs:86:5
[INFO] [stderr]    |
[INFO] [stderr] 86 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `read_lock`
[INFO] [stderr]   --> src/lib.rs:75:5
[INFO] [stderr]    |
[INFO] [stderr] 75 |     read_lock: Option<RwLockReadGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `write_lock`
[INFO] [stderr]   --> src/lib.rs:76:5
[INFO] [stderr]    |
[INFO] [stderr] 76 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 7.79s
[INFO] running `"docker" "inspect" "3ed7956fd28910d0aea7b185342682851495cc14651fdd45298b006984083975"`
[INFO] running `"docker" "rm" "-f" "3ed7956fd28910d0aea7b185342682851495cc14651fdd45298b006984083975"`
[INFO] [stdout] 3ed7956fd28910d0aea7b185342682851495cc14651fdd45298b006984083975