[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 try#cac44d9528e3bbbdaa1537d187bd489ccc5de18c for pr-91141
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsteinsag%2Frust-connect4" "/workspace/builds/worker-87/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-87/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/steinsag/rust-connect4 on toolchain cac44d9528e3bbbdaa1537d187bd489ccc5de18c
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+cac44d9528e3bbbdaa1537d187bd489ccc5de18c" "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-87/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" "+cac44d9528e3bbbdaa1537d187bd489ccc5de18c" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-87/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-87/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+cac44d9528e3bbbdaa1537d187bd489ccc5de18c" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 40e74d104acfeadccb573ebef936a58046a9f741418696326a7cd99fa561de75
[INFO] running `Command { std: "docker" "start" "-a" "40e74d104acfeadccb573ebef936a58046a9f741418696326a7cd99fa561de75", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "40e74d104acfeadccb573ebef936a58046a9f741418696326a7cd99fa561de75", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "40e74d104acfeadccb573ebef936a58046a9f741418696326a7cd99fa561de75", kill_on_drop: false }`
[INFO] [stdout] 40e74d104acfeadccb573ebef936a58046a9f741418696326a7cd99fa561de75
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-87/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-87/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+cac44d9528e3bbbdaa1537d187bd489ccc5de18c" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] aa18621f7c4eb838e257a2cb97c1e3cc7658563bf6b4a7a3073f0a4681441c92
[INFO] running `Command { std: "docker" "start" "-a" "aa18621f7c4eb838e257a2cb97c1e3cc7658563bf6b4a7a3073f0a4681441c92", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking ppv-lite86 v0.2.9
[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] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 36.89s
[INFO] running `Command { std: "docker" "inspect" "aa18621f7c4eb838e257a2cb97c1e3cc7658563bf6b4a7a3073f0a4681441c92", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aa18621f7c4eb838e257a2cb97c1e3cc7658563bf6b4a7a3073f0a4681441c92", kill_on_drop: false }`
[INFO] [stdout] aa18621f7c4eb838e257a2cb97c1e3cc7658563bf6b4a7a3073f0a4681441c92