[INFO] updating cached repository https://github.com/lklacar/rust-tic-tac-toe-ai
[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] 4071d4f333eaf0b602d2deaa041e398bf8e3f014
[INFO] checking lklacar/rust-tic-tac-toe-ai against master#4ff32c07da9d97e6dc315a4a5c9ffbb797cb27bb for pr-64672
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Flklacar%2Frust-tic-tac-toe-ai" "work/builds/worker-3/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lklacar/rust-tic-tac-toe-ai on toolchain 4ff32c07da9d97e6dc315a4a5c9ffbb797cb27bb
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+4ff32c07da9d97e6dc315a4a5c9ffbb797cb27bb" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/lklacar/rust-tic-tac-toe-ai
[INFO] finished tweaking git repo https://github.com/lklacar/rust-tic-tac-toe-ai
[INFO] tweaked toml for git repo https://github.com/lklacar/rust-tic-tac-toe-ai written to work/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/lklacar/rust-tic-tac-toe-ai already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+4ff32c07da9d97e6dc315a4a5c9ffbb797cb27bb" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/mnt/big/crater/work/builds/worker-3/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" "+4ff32c07da9d97e6dc315a4a5c9ffbb797cb27bb" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 3aff7caeae2dd1d69f57f961720e07e58c0edec3fc750f195a71bea23b984845
[INFO] running `"docker" "start" "-a" "3aff7caeae2dd1d69f57f961720e07e58c0edec3fc750f195a71bea23b984845"`
[INFO] [stderr]     Checking rust-tic-tac-toe-ai v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `size`
[INFO] [stderr]   --> src/board.rs:10:16
[INFO] [stderr]    |
[INFO] [stderr] 10 |     pub fn new(size: u32) -> Board {
[INFO] [stderr]    |                ^^^^ help: consider prefixing with an underscore: `_size`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `cell`
[INFO] [stderr]   --> src/board.rs:51:17
[INFO] [stderr]    |
[INFO] [stderr] 51 |         let mut cell = match option_cell {
[INFO] [stderr]    |                 ^^^^ help: consider prefixing with an underscore: `_cell`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/board.rs:51:13
[INFO] [stderr]    |
[INFO] [stderr] 51 |         let mut cell = match option_cell {
[INFO] [stderr]    |             ----^^^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/board.rs:74:21
[INFO] [stderr]    |
[INFO] [stderr] 74 |                 let mut cell = match option_cell {
[INFO] [stderr]    |                     ----^^^^
[INFO] [stderr]    |                     |
[INFO] [stderr]    |                     help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `empty_cells`
[INFO] [stderr]   --> src/board.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn empty_cells(&self) -> Vec<&cell::Cell> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `O`
[INFO] [stderr]  --> src/cell.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 |     O,
[INFO] [stderr]   |     ^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `size`
[INFO] [stderr]   --> src/board.rs:10:16
[INFO] [stderr]    |
[INFO] [stderr] 10 |     pub fn new(size: u32) -> Board {
[INFO] [stderr]    |                ^^^^ help: consider prefixing with an underscore: `_size`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `cell`
[INFO] [stderr]   --> src/board.rs:51:17
[INFO] [stderr]    |
[INFO] [stderr] 51 |         let mut cell = match option_cell {
[INFO] [stderr]    |                 ^^^^ help: consider prefixing with an underscore: `_cell`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/board.rs:51:13
[INFO] [stderr]    |
[INFO] [stderr] 51 |         let mut cell = match option_cell {
[INFO] [stderr]    |             ----^^^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/board.rs:74:21
[INFO] [stderr]    |
[INFO] [stderr] 74 |                 let mut cell = match option_cell {
[INFO] [stderr]    |                     ----^^^^
[INFO] [stderr]    |                     |
[INFO] [stderr]    |                     help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `empty_cells`
[INFO] [stderr]   --> src/board.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn empty_cells(&self) -> Vec<&cell::Cell> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `O`
[INFO] [stderr]  --> src/cell.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 |     O,
[INFO] [stderr]   |     ^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.82s
[INFO] running `"docker" "inspect" "3aff7caeae2dd1d69f57f961720e07e58c0edec3fc750f195a71bea23b984845"`
[INFO] running `"docker" "rm" "-f" "3aff7caeae2dd1d69f57f961720e07e58c0edec3fc750f195a71bea23b984845"`
[INFO] [stdout] 3aff7caeae2dd1d69f57f961720e07e58c0edec3fc750f195a71bea23b984845