[INFO] fetching crate maybe-single 0.12.0...
[INFO] checking maybe-single-0.12.0 against master#0dce3f606e05cffab7361c132a399d3550ab0df8 for pr-78376
[INFO] extracting crate maybe-single 0.12.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate maybe-single 0.12.0 on toolchain 0dce3f606e05cffab7361c132a399d3550ab0df8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "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-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b38df67fc4c88a0d6f0114e2e8e9b9a0179b54d52502989903f2693db212bba6
[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" "b38df67fc4c88a0d6f0114e2e8e9b9a0179b54d52502989903f2693db212bba6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b38df67fc4c88a0d6f0114e2e8e9b9a0179b54d52502989903f2693db212bba6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b38df67fc4c88a0d6f0114e2e8e9b9a0179b54d52502989903f2693db212bba6", kill_on_drop: false }`
[INFO] [stdout] b38df67fc4c88a0d6f0114e2e8e9b9a0179b54d52502989903f2693db212bba6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1e7ef1ae24eb0866e50795914e37e741188836dc7967efa06cd870fa39e3030b
[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" "1e7ef1ae24eb0866e50795914e37e741188836dc7967efa06cd870fa39e3030b", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]     Checking smallvec v1.4.2
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]     Checking arc-swap v0.4.7
[INFO] [stderr]     Checking fnv v1.0.7
[INFO] [stderr]     Checking pin-project-lite v0.1.11
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking futures-core v0.3.7
[INFO] [stderr]     Checking log v0.4.11
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking net2 v0.2.35
[INFO] [stderr]     Checking getrandom v0.1.15
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking parking_lot_core v0.7.2
[INFO] [stderr]     Checking signal-hook-registry v1.2.1
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking parking_lot v0.10.2
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]    Compiling syn v1.0.48
[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]     Checking mio-uds v0.6.8
[INFO] [stderr]    Compiling tokio-macros v0.2.5
[INFO] [stderr]     Checking tokio v0.2.22
[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 27.95s
[INFO] running `Command { std: "docker" "inspect" "1e7ef1ae24eb0866e50795914e37e741188836dc7967efa06cd870fa39e3030b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1e7ef1ae24eb0866e50795914e37e741188836dc7967efa06cd870fa39e3030b", kill_on_drop: false }`
[INFO] [stdout] 1e7ef1ae24eb0866e50795914e37e741188836dc7967efa06cd870fa39e3030b