[INFO] cloning repository https://github.com/JettTech/rust-async-workshop
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/JettTech/rust-async-workshop" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJettTech%2Frust-async-workshop", kill_on_drop: false }`
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[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 81ee361f04c4fe1a3b7a0a1eb644a2f1a2cb1fc0
[INFO] testing JettTech/rust-async-workshop against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJettTech%2Frust-async-workshop" "/workspace/builds/worker-65/source", kill_on_drop: false }`
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[INFO] validating manifest of git repo https://github.com/JettTech/rust-async-workshop on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
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[INFO] tweaked toml for git repo https://github.com/JettTech/rust-async-workshop written to /workspace/builds/worker-65/source/Cargo.toml
[INFO] crate git repo https://github.com/JettTech/rust-async-workshop already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
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[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-65/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-65/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
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[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-65/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-65/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=warn" "-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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
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[INFO] [stderr]    Compiling client v0.0.0 (/opt/rustwide/workdir/client)
[INFO] [stderr]    Compiling server v0.0.0 (/opt/rustwide/workdir/server)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> client/src/../solutions/client.rs:10:39
[INFO] [stdout]    |
[INFO] [stdout] 10 | pub async fn run_client(user: String, mut stream: TcpStream) -> Result<(), Error> {
[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] error[E0277]: the `?` operator can only be used in an async block that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> client/src/main.rs:31:48
[INFO] [stdout]    |
[INFO] [stdout] 25 | #[tokio::main]
[INFO] [stdout]    | -------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 31 |     let conn = TcpStream::connect(server).await?;
[INFO] [stdout]    |                                                ^ cannot use the `?` operator in an async block that returns `()`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]   --> client/src/main.rs:25:1
[INFO] [stdout]    |
[INFO] [stdout] 25 | #[tokio::main]
[INFO] [stdout]    | ^^^^^^^^^^^^^^ expected enum `Result`, found `()`
[INFO] [stdout] 26 | async fn main() -> Result<(), client::Error> {
[INFO] [stdout]    |                    ------------------------- expected `Result<(), Box<(dyn std::error::Error + 'static)>>` because of return type
[INFO] [stdout]    |
[INFO] [stdout]    = note:   expected enum `Result<(), Box<(dyn std::error::Error + 'static)>>`
[INFO] [stdout]            found unit type `()`
[INFO] [stdout]    = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] help: try adding an expression at the end of the block
[INFO] [stdout]    |
[INFO] [stdout] 25 ~ #[tokio::main];
[INFO] [stdout] 26 + Ok(())
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0308.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `client` due to 3 previous errors; 1 warning emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "64004ea956bec5eca5e279038cba385ce56446bc5a4d75e4064e5a7dfa817487", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "64004ea956bec5eca5e279038cba385ce56446bc5a4d75e4064e5a7dfa817487", kill_on_drop: false }`
[INFO] [stdout] 64004ea956bec5eca5e279038cba385ce56446bc5a4d75e4064e5a7dfa817487