[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 try#f47dd4da3ae8c32c9e65d307bfe640b143e674df for pr-77526
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsabahtalateh%2Frust-async-book" "/workspace/builds/worker-5/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sabahtalateh/rust-async-book on toolchain f47dd4da3ae8c32c9e65d307bfe640b143e674df
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "read-manifest" "--manifest-path" "Cargo.toml", 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-5/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" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0923f914e41c0c3075eba56c87735a1dfb8b76ae74812c498f9ff097ee4abd24
[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" "0923f914e41c0c3075eba56c87735a1dfb8b76ae74812c498f9ff097ee4abd24", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0923f914e41c0c3075eba56c87735a1dfb8b76ae74812c498f9ff097ee4abd24", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0923f914e41c0c3075eba56c87735a1dfb8b76ae74812c498f9ff097ee4abd24", kill_on_drop: false }`
[INFO] [stdout] 0923f914e41c0c3075eba56c87735a1dfb8b76ae74812c498f9ff097ee4abd24
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f972329926b7ee905b1b1e301d25aa66be8ff52feecb4056c065f4b55ce62fc5
[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" "f972329926b7ee905b1b1e301d25aa66be8ff52feecb4056c065f4b55ce62fc5", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling httparse v1.3.4
[INFO] [stderr]     Checking tokio-sync v0.1.6
[INFO] [stderr]     Checking want v0.2.0
[INFO] [stderr]     Checking futures-cpupool v0.1.8
[INFO] [stderr]     Checking tokio-io v0.1.12
[INFO] [stderr]     Checking tokio-buf v0.1.1
[INFO] [stderr]     Checking crossbeam-utils v0.6.6
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking http-body v0.1.0
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking tokio-executor v0.1.8
[INFO] [stderr]     Checking crossbeam-queue v0.1.2
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking h2 v0.1.26
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]     Checking tokio-timer v0.2.11
[INFO] [stderr]     Checking tokio-current-thread v0.1.6
[INFO] [stderr]    Compiling parking_lot_core v0.4.0
[INFO] [stderr]    Compiling memoffset v0.5.1
[INFO] [stderr]    Compiling hyper v0.12.34
[INFO] [stderr]     Checking crossbeam-epoch v0.7.2
[INFO] [stderr]     Checking parking_lot v0.7.1
[INFO] [stderr]     Checking crossbeam-deque v0.7.1
[INFO] [stderr]     Checking tokio-reactor v0.1.9
[INFO] [stderr]     Checking tokio-threadpool v0.1.15
[INFO] [stderr]     Checking tokio-tcp v0.1.3
[INFO] [stderr]     Checking tokio v0.1.22
[INFO] [stderr]     Checking futures-executor-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking futures-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking async-await-echo v0.1.0 (/opt/rustwide/workdir)
[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: 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: 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: 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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::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: unused `std::result::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: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 30.80s
[INFO] running `Command { std: "docker" "inspect" "f972329926b7ee905b1b1e301d25aa66be8ff52feecb4056c065f4b55ce62fc5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f972329926b7ee905b1b1e301d25aa66be8ff52feecb4056c065f4b55ce62fc5", kill_on_drop: false }`
[INFO] [stdout] f972329926b7ee905b1b1e301d25aa66be8ff52feecb4056c065f4b55ce62fc5