[INFO] fetching crate maybe-single 0.15.0...
[INFO] checking maybe-single-0.15.0 against try#8de4b308b608cded0ebccf658a0fc719bce87d4e for pr-89056
[INFO] extracting crate maybe-single 0.15.0 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate maybe-single 0.15.0 on toolchain 8de4b308b608cded0ebccf658a0fc719bce87d4e
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8de4b308b608cded0ebccf658a0fc719bce87d4e" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate maybe-single 0.15.0
[INFO] finished tweaking crates.io crate maybe-single 0.15.0
[INFO] tweaked toml for crates.io crate maybe-single 0.15.0 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8de4b308b608cded0ebccf658a0fc719bce87d4e" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8de4b308b608cded0ebccf658a0fc719bce87d4e" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+8de4b308b608cded0ebccf658a0fc719bce87d4e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4d463a1ad2a84f043e1a3794b80f0c33eb878bcb0cf7541bae65a948401b9478
[INFO] running `Command { std: "docker" "start" "-a" "4d463a1ad2a84f043e1a3794b80f0c33eb878bcb0cf7541bae65a948401b9478", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4d463a1ad2a84f043e1a3794b80f0c33eb878bcb0cf7541bae65a948401b9478", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d463a1ad2a84f043e1a3794b80f0c33eb878bcb0cf7541bae65a948401b9478", kill_on_drop: false }`
[INFO] [stdout] 4d463a1ad2a84f043e1a3794b80f0c33eb878bcb0cf7541bae65a948401b9478
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+8de4b308b608cded0ebccf658a0fc719bce87d4e" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fac354e9b8ccf5a29ae9346dd5d65c01e207d11902023bd99534ec1b6191d916
[INFO] running `Command { std: "docker" "start" "-a" "fac354e9b8ccf5a29ae9346dd5d65c01e207d11902023bd99534ec1b6191d916", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]     Checking pin-project-lite v0.2.7
[INFO] [stderr]     Checking instant v0.1.10
[INFO] [stderr]     Checking getrandom v0.2.3
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking parking_lot_core v0.8.5
[INFO] [stderr]     Checking lock_api v0.4.5
[INFO] [stderr]     Checking rand_core v0.6.3
[INFO] [stderr]     Checking parking_lot v0.11.2
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]    Compiling tokio v1.11.0
[INFO] [stderr]     Checking maybe-single v0.15.0 (/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] [stderr]     Checking rand v0.8.4
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling tokio-macros v1.3.0
[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 11.19s
[INFO] running `Command { std: "docker" "inspect" "fac354e9b8ccf5a29ae9346dd5d65c01e207d11902023bd99534ec1b6191d916", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fac354e9b8ccf5a29ae9346dd5d65c01e207d11902023bd99534ec1b6191d916", kill_on_drop: false }`
[INFO] [stdout] fac354e9b8ccf5a29ae9346dd5d65c01e207d11902023bd99534ec1b6191d916