[INFO] cloning repository https://github.com/steinsag/rust-connect4
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/steinsag/rust-connect4" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsteinsag%2Frust-connect4", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsteinsag%2Frust-connect4'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d9d3f098247097ab3f65e5006b1196bb331e82e7
[INFO] checking steinsag/rust-connect4 against master#f82664191d0e8764b7435b9d72eb0e366b8b1464 for pr-83354
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsteinsag%2Frust-connect4" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/steinsag/rust-connect4 on toolchain f82664191d0e8764b7435b9d72eb0e366b8b1464
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/steinsag/rust-connect4
[INFO] finished tweaking git repo https://github.com/steinsag/rust-connect4
[INFO] tweaked toml for git repo https://github.com/steinsag/rust-connect4 written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/steinsag/rust-connect4 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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@sha256:4f92631de1aa59f8320307485d3b3c869a5c90ab1d76ce2cffab9807b8c9a1fb" "/opt/rustwide/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 461d6662bc48d4d78c0bd569ca2f72ec9dbefdd9e176d0bce45ce5abb8a2d387
[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" "461d6662bc48d4d78c0bd569ca2f72ec9dbefdd9e176d0bce45ce5abb8a2d387", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "461d6662bc48d4d78c0bd569ca2f72ec9dbefdd9e176d0bce45ce5abb8a2d387", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "461d6662bc48d4d78c0bd569ca2f72ec9dbefdd9e176d0bce45ce5abb8a2d387", kill_on_drop: false }`
[INFO] [stdout] 461d6662bc48d4d78c0bd569ca2f72ec9dbefdd9e176d0bce45ce5abb8a2d387
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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@sha256:4f92631de1aa59f8320307485d3b3c869a5c90ab1d76ce2cffab9807b8c9a1fb" "/opt/rustwide/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a9862fd7f00c95fae668b9ecf6eea50d288156b73f375250ea77bceb30e338ab
[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" "a9862fd7f00c95fae668b9ecf6eea50d288156b73f375250ea77bceb30e338ab", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]     Checking ppv-lite86 v0.2.9
[INFO] [stderr]     Checking getrandom v0.1.15
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking connect4 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `temporary_game_field`
[INFO] [stdout]   --> src/strategy/back_propagation.rs:18:17
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let mut temporary_game_field = board.clone();
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_temporary_game_field`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `col`
[INFO] [stdout]   --> src/strategy/back_propagation.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         for col in 0..COLS {}
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_col`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/strategy/back_propagation.rs:18:13
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let mut temporary_game_field = board.clone();
[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: field is never read: `pushed_columns`
[INFO] [stdout]  --> src/strategy/back_propagation.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     pushed_columns: Vec<u8>,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `temporary_game_field`
[INFO] [stdout]   --> src/strategy/back_propagation.rs:18:17
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let mut temporary_game_field = board.clone();
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_temporary_game_field`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `col`
[INFO] [stdout]   --> src/strategy/back_propagation.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         for col in 0..COLS {}
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_col`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/strategy/back_propagation.rs:18:13
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let mut temporary_game_field = board.clone();
[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: field is never read: `pushed_columns`
[INFO] [stdout]  --> src/strategy/back_propagation.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     pushed_columns: Vec<u8>,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.76s
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "a9862fd7f00c95fae668b9ecf6eea50d288156b73f375250ea77bceb30e338ab", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a9862fd7f00c95fae668b9ecf6eea50d288156b73f375250ea77bceb30e338ab", kill_on_drop: false }`
[INFO] [stdout] a9862fd7f00c95fae668b9ecf6eea50d288156b73f375250ea77bceb30e338ab