[INFO] updating cached repository https://github.com/nougator/Voxena
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] d742ee8ac8ecbdc7e9eddf51362be8fbf975e1d9
[INFO] checking nougator/Voxena against try#8a749131e7beb72f6edacefd2bdcbed3d67b2112 for pr-72331
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnougator%2FVoxena" "/workspace/builds/worker-12/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nougator/Voxena on toolchain 8a749131e7beb72f6edacefd2bdcbed3d67b2112
[INFO] running `"/workspace/cargo-home/bin/cargo" "+8a749131e7beb72f6edacefd2bdcbed3d67b2112" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/nougator/Voxena
[INFO] finished tweaking git repo https://github.com/nougator/Voxena
[INFO] tweaked toml for git repo https://github.com/nougator/Voxena written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/nougator/Voxena already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+8a749131e7beb72f6edacefd2bdcbed3d67b2112" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+8a749131e7beb72f6edacefd2bdcbed3d67b2112" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f1dbd2baf313b59788c0a3a989724e44c9592d6427a07274e1fcb33d914c24bd
[INFO] running `"docker" "start" "-a" "f1dbd2baf313b59788c0a3a989724e44c9592d6427a07274e1fcb33d914c24bd"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]     Checking Voxena v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused imports: `ErrorKind`, `Read`, `Write`
[INFO] [stderr]  --> src/main.rs:1:15
[INFO] [stderr]   |
[INFO] [stderr] 1 | use std::io::{ErrorKind, Read, Write};
[INFO] [stderr]   |               ^^^^^^^^^  ^^^^  ^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::sync::mpsc`
[INFO] [stderr]  --> src/main.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::sync::mpsc;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::thread`
[INFO] [stderr]  --> src/main.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use std::thread;
[INFO] [stderr]   |     ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `ErrorKind`, `Read`, `Write`
[INFO] [stderr]  --> src/main.rs:1:15
[INFO] [stderr]   |
[INFO] [stderr] 1 | use std::io::{ErrorKind, Read, Write};
[INFO] [stderr]   |               ^^^^^^^^^  ^^^^  ^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::sync::mpsc`
[INFO] [stderr]  --> src/main.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::sync::mpsc;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::thread`
[INFO] [stderr]  --> src/main.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use std::thread;
[INFO] [stderr]   |     ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
[INFO] [stderr]   --> src/main.rs:11:22
[INFO] [stderr]    |
[INFO] [stderr] 10 | / fn main() {
[INFO] [stderr] 11 | |     let mut socket = UdpSocket::bind(HOST)?;
[INFO] [stderr]    | |                      ^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stderr] 12 | |     let mut buf = [0; 10];
[INFO] [stderr] 13 | | }
[INFO] [stderr]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the trait `std::ops::Try` is not implemented for `()`
[INFO] [stderr]    = note: required by `std::ops::Try::from_error`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error; 3 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0277`.
[INFO] [stderr] error: could not compile `Voxena`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
[INFO] [stderr]   --> src/main.rs:11:22
[INFO] [stderr]    |
[INFO] [stderr] 10 | / fn main() {
[INFO] [stderr] 11 | |     let mut socket = UdpSocket::bind(HOST)?;
[INFO] [stderr]    | |                      ^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stderr] 12 | |     let mut buf = [0; 10];
[INFO] [stderr] 13 | | }
[INFO] [stderr]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the trait `std::ops::Try` is not implemented for `()`
[INFO] [stderr]    = note: required by `std::ops::Try::from_error`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error; 3 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0277`.
[INFO] [stderr] error: could not compile `Voxena`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "f1dbd2baf313b59788c0a3a989724e44c9592d6427a07274e1fcb33d914c24bd"`
[INFO] running `"docker" "rm" "-f" "f1dbd2baf313b59788c0a3a989724e44c9592d6427a07274e1fcb33d914c24bd"`
[INFO] [stdout] f1dbd2baf313b59788c0a3a989724e44c9592d6427a07274e1fcb33d914c24bd