[INFO] fetching crate maybe-single 0.14.0...
[INFO] checking maybe-single-0.14.0 against master#50e1dc1536264ab71c0850f346b12309477f29f7 for pr-85073
[INFO] extracting crate maybe-single 0.14.0 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate maybe-single 0.14.0 on toolchain 50e1dc1536264ab71c0850f346b12309477f29f7
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+50e1dc1536264ab71c0850f346b12309477f29f7" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate maybe-single 0.14.0
[INFO] finished tweaking crates.io crate maybe-single 0.14.0
[INFO] tweaked toml for crates.io crate maybe-single 0.14.0 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+50e1dc1536264ab71c0850f346b12309477f29f7" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+50e1dc1536264ab71c0850f346b12309477f29f7" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+50e1dc1536264ab71c0850f346b12309477f29f7" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7bffc5126a9796e4c02d6e7b3f80657b84f2926567b0e542d33a560c1eed27f8
[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" "7bffc5126a9796e4c02d6e7b3f80657b84f2926567b0e542d33a560c1eed27f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7bffc5126a9796e4c02d6e7b3f80657b84f2926567b0e542d33a560c1eed27f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7bffc5126a9796e4c02d6e7b3f80657b84f2926567b0e542d33a560c1eed27f8", kill_on_drop: false }`
[INFO] [stdout] 7bffc5126a9796e4c02d6e7b3f80657b84f2926567b0e542d33a560c1eed27f8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+50e1dc1536264ab71c0850f346b12309477f29f7" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 41f4c98b9eb52e6954506cc948d206fbb5656716658d1cd8801ba795a4db6ff0
[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" "41f4c98b9eb52e6954506cc948d206fbb5656716658d1cd8801ba795a4db6ff0", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.27
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.72
[INFO] [stderr]     Checking pin-project-lite v0.2.6
[INFO] [stderr]     Checking once_cell v1.7.2
[INFO] [stderr]     Checking instant v0.1.9
[INFO] [stderr]    Compiling tokio v1.6.0
[INFO] [stderr]     Checking getrandom v0.2.3
[INFO] [stderr]     Checking parking_lot_core v0.8.3
[INFO] [stderr]     Checking rand_core v0.6.2
[INFO] [stderr]     Checking parking_lot v0.11.1
[INFO] [stderr]     Checking rand_chacha v0.3.0
[INFO] [stderr]     Checking maybe-single v0.14.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `read_lock`
[INFO] [stdout]   --> src/blocking.rs:73:5
[INFO] [stdout]    |
[INFO] [stdout] 73 |     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/blocking.rs:74:5
[INFO] [stdout]    |
[INFO] [stdout] 74 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking rand v0.8.3
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling tokio-macros v1.2.0
[INFO] [stdout] warning: field is never read: `read_lock`
[INFO] [stdout]   --> src/blocking.rs:73:5
[INFO] [stdout]    |
[INFO] [stdout] 73 |     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/blocking.rs:74:5
[INFO] [stdout]    |
[INFO] [stdout] 74 |     write_lock: Option<RwLockWriteGuard<'a, ()>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 19.83s
[INFO] running `Command { std: "docker" "inspect" "41f4c98b9eb52e6954506cc948d206fbb5656716658d1cd8801ba795a4db6ff0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "41f4c98b9eb52e6954506cc948d206fbb5656716658d1cd8801ba795a4db6ff0", kill_on_drop: false }`
[INFO] [stdout] 41f4c98b9eb52e6954506cc948d206fbb5656716658d1cd8801ba795a4db6ff0