[INFO] cloning repository https://github.com/sabahtalateh/rust-async-book
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sabahtalateh/rust-async-book" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsabahtalateh%2Frust-async-book", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsabahtalateh%2Frust-async-book'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1f1be3396332455f288719bd2f163fba11b7f47d
[INFO] checking sabahtalateh/rust-async-book against master#5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsabahtalateh%2Frust-async-book" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sabahtalateh/rust-async-book on toolchain 5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sabahtalateh/rust-async-book
[INFO] finished tweaking git repo https://github.com/sabahtalateh/rust-async-book
[INFO] tweaked toml for git repo https://github.com/sabahtalateh/rust-async-book written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/sabahtalateh/rust-async-book already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 177eb66a26c1c8de12bdb8cb2c396168a38043ce344a151a753fd4fdf0c48b9b
[INFO] running `Command { std: "docker" "start" "-a" "177eb66a26c1c8de12bdb8cb2c396168a38043ce344a151a753fd4fdf0c48b9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "177eb66a26c1c8de12bdb8cb2c396168a38043ce344a151a753fd4fdf0c48b9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "177eb66a26c1c8de12bdb8cb2c396168a38043ce344a151a753fd4fdf0c48b9b", kill_on_drop: false }`
[INFO] [stdout] 177eb66a26c1c8de12bdb8cb2c396168a38043ce344a151a753fd4fdf0c48b9b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] db76d21b604300b50a00eedd530600eb9494dfb3925768353e598ef04afccdd7
[INFO] running `Command { std: "docker" "start" "-a" "db76d21b604300b50a00eedd530600eb9494dfb3925768353e598ef04afccdd7", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking either v1.5.2
[INFO] [stderr]     Checking fnv v1.0.6
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[INFO] [stderr]     Checking nodrop v0.1.13
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[INFO] [stderr]    Compiling httparse v1.3.4
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking indexmap v1.1.0
[INFO] [stderr]     Checking try-lock v0.2.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking rand_jitter v0.1.4
[INFO] [stderr]     Checking rand_xorshift v0.1.1
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[INFO] [stderr]     Checking tokio-current-thread v0.1.6
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[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking num_cpus v1.10.1
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[INFO] [stdout] warning: unused import: `std::process::Output`
[INFO] [stdout]  --> src/bin/executor.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::process::Output;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/bin/pin.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let a = "1".as_bytes().to_vec();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/event_loop.rs:52:20
[INFO] [stdout]    |
[INFO] [stdout] 52 |                 Ok(mut t) => {
[INFO] [stdout]    |                    ----^
[INFO] [stdout]    |                    |
[INFO] [stdout]    |                    help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/bin/pin.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let a = "1".as_bytes().to_vec();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::process::Output`
[INFO] [stdout]  --> src/bin/executor.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::process::Output;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/bin/event_loop.rs:38:9
[INFO] [stdout]    |
[INFO] [stdout] 38 |         self.tasks_sender.send(task);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/event_loop.rs:52:20
[INFO] [stdout]    |
[INFO] [stdout] 52 |                 Ok(mut t) => {
[INFO] [stdout]    |                    ----^
[INFO] [stdout]    |                    |
[INFO] [stdout]    |                    help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/bin/event_loop.rs:38:9
[INFO] [stdout]    |
[INFO] [stdout] 38 |         self.tasks_sender.send(task);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 20.10s
[INFO] running `Command { std: "docker" "inspect" "db76d21b604300b50a00eedd530600eb9494dfb3925768353e598ef04afccdd7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "db76d21b604300b50a00eedd530600eb9494dfb3925768353e598ef04afccdd7", kill_on_drop: false }`
[INFO] [stdout] db76d21b604300b50a00eedd530600eb9494dfb3925768353e598ef04afccdd7