[INFO] fetching crate cb_fut 0.2.1...
[INFO] checking cb_fut-0.2.1 against try#45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4 for pr-83744
[INFO] extracting crate cb_fut 0.2.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate cb_fut 0.2.1 on toolchain 45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate cb_fut 0.2.1
[INFO] finished tweaking crates.io crate cb_fut 0.2.1
[INFO] tweaked toml for crates.io crate cb_fut 0.2.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded crossbeam-channel v0.4.4
[INFO] [stderr]   Downloaded crossbeam-utils v0.7.2
[INFO] [stderr]   Downloaded maybe-uninit v2.0.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/jobserver:/tmp/crater-runner-fifo:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cb692e02d8cbefb1f7e7e15dbe2e779e1ac93a58f419c9e750182f318a7c5e63
[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" "cb692e02d8cbefb1f7e7e15dbe2e779e1ac93a58f419c9e750182f318a7c5e63", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cb692e02d8cbefb1f7e7e15dbe2e779e1ac93a58f419c9e750182f318a7c5e63", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cb692e02d8cbefb1f7e7e15dbe2e779e1ac93a58f419c9e750182f318a7c5e63", kill_on_drop: false }`
[INFO] [stdout] cb692e02d8cbefb1f7e7e15dbe2e779e1ac93a58f419c9e750182f318a7c5e63
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/jobserver:/tmp/crater-runner-fifo:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "RUSTUP_TOOLCHAIN=45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "-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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/tmp/crater-runner-fifo/jobserver-crater-fwd" "/opt/rustwide/cargo-home/bin/cargo" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 55027d21d0c3f67720d8f9866c0a4d33746f8ed3b60ba9b08ff4b2d42aa752bb
[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" "55027d21d0c3f67720d8f9866c0a4d33746f8ed3b60ba9b08ff4b2d42aa752bb", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.69
[INFO] [stderr]    Compiling libc v0.2.93
[INFO] [stderr]     Checking futures-core v0.3.14
[INFO] [stderr]     Checking futures-channel v0.3.14
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]    Compiling futures-macro v0.3.14
[INFO] [stderr]     Checking futures-util v0.3.14
[INFO] [stderr]     Checking futures-executor v0.3.14
[INFO] [stderr]     Checking futures v0.3.14
[INFO] [stderr]     Checking cb_fut v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary braces around method argument
[INFO] [stdout]    --> src/lib.rs:666:71
[INFO] [stdout]     |
[INFO] [stdout] 666 |         futures::executor::block_on(once_blocked!(func(2 + 3, ->() -> {3i32})));
[INFO] [stdout]     |                                                                       ^^^^^^ help: remove these braces
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_braces)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary braces around method argument
[INFO] [stdout]    --> src/lib.rs:728:64
[INFO] [stdout]     |
[INFO] [stdout] 728 |         futures::executor::block_on(once_blocked!(func(->() -> {3i32}, 2 + 3)));
[INFO] [stdout]     |                                                                ^^^^^^ help: remove these braces
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `waker`
[INFO] [stdout]    --> src/lib.rs:400:5
[INFO] [stdout]     |
[INFO] [stdout] 400 |     waker: Option<futures::task::Waker>
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `waker`
[INFO] [stdout]    --> src/lib.rs:445:5
[INFO] [stdout]     |
[INFO] [stdout] 445 |     waker: Option<futures::task::Waker>
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `waker`
[INFO] [stdout]    --> src/lib.rs:400:5
[INFO] [stdout]     |
[INFO] [stdout] 400 |     waker: Option<futures::task::Waker>
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `waker`
[INFO] [stdout]    --> src/lib.rs:445:5
[INFO] [stdout]     |
[INFO] [stdout] 445 |     waker: Option<futures::task::Waker>
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 31.96s
[INFO] running `Command { std: "docker" "inspect" "55027d21d0c3f67720d8f9866c0a4d33746f8ed3b60ba9b08ff4b2d42aa752bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "55027d21d0c3f67720d8f9866c0a4d33746f8ed3b60ba9b08ff4b2d42aa752bb", kill_on_drop: false }`
[INFO] [stdout] 55027d21d0c3f67720d8f9866c0a4d33746f8ed3b60ba9b08ff4b2d42aa752bb