[INFO] updating cached repository https://github.com/ravendyg/rust-playground
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/mnt/big/crater/work/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] f0fbaf1c751f3fbfd6b05d9779721bfa5fc7f25f
[INFO] checking ravendyg/rust-playground against master#c9edc02e8320a9e5799d185910ece7d491f524e6 for pr-64398
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fravendyg%2Frust-playground" "work/builds/worker-5/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-5/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ravendyg/rust-playground on toolchain c9edc02e8320a9e5799d185910ece7d491f524e6-alt
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/ravendyg/rust-playground
[INFO] finished tweaking git repo https://github.com/ravendyg/rust-playground
[INFO] tweaked toml for git repo https://github.com/ravendyg/rust-playground written to work/builds/worker-5/source/Cargo.toml
[INFO] crate git repo https://github.com/ravendyg/rust-playground already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/mnt/big/crater/work/builds/worker-5/source:/opt/rustwide/workdir:ro,Z" "-v" "/mnt/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 69eefa9e259c9029d259eaa01134638850581cda7593063e192f74725f186342
[INFO] running `"docker" "start" "-a" "69eefa9e259c9029d259eaa01134638850581cda7593063e192f74725f186342"`
[INFO] [stderr]     Checking guessing v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/main.rs:60:7
[INFO] [stderr]    |
[INFO] [stderr] 60 |   let x: Option<i32> = Option::Some(5);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `q`
[INFO] [stderr]   --> src/main.rs:62:7
[INFO] [stderr]    |
[INFO] [stderr] 62 |   let q: Option<f64> = Option::Some(5f64);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_q`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `b`
[INFO] [stderr]   --> src/main.rs:71:7
[INFO] [stderr]    |
[INFO] [stderr] 71 |   let b = 10;
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_b`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/main.rs:49:3
[INFO] [stderr]    |
[INFO] [stderr] 49 |   None
[INFO] [stderr]    |   ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Result`
[INFO] [stderr]   --> src/main.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | enum Result<T, E> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/main.rs:60:7
[INFO] [stderr]    |
[INFO] [stderr] 60 |   let x: Option<i32> = Option::Some(5);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `q`
[INFO] [stderr]   --> src/main.rs:62:7
[INFO] [stderr]    |
[INFO] [stderr] 62 |   let q: Option<f64> = Option::Some(5f64);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_q`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `b`
[INFO] [stderr]   --> src/main.rs:71:7
[INFO] [stderr]    |
[INFO] [stderr] 71 |   let b = 10;
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_b`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/main.rs:49:3
[INFO] [stderr]    |
[INFO] [stderr] 49 |   None
[INFO] [stderr]    |   ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Result`
[INFO] [stderr]   --> src/main.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | enum Result<T, E> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.37s
[INFO] running `"docker" "inspect" "69eefa9e259c9029d259eaa01134638850581cda7593063e192f74725f186342"`
[INFO] running `"docker" "rm" "-f" "69eefa9e259c9029d259eaa01134638850581cda7593063e192f74725f186342"`
[INFO] [stdout] 69eefa9e259c9029d259eaa01134638850581cda7593063e192f74725f186342