[INFO] cloning repository https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/BenSandeen/sudoku-hinter-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 02a14a4d9e64deede268ed1df6b10ac0efb67e03
[INFO] testing BenSandeen/sudoku-hinter-rs against 1.47.0 for beta-1.48-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/BenSandeen/sudoku-hinter-rs on toolchain 1.47.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] finished tweaking git repo https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] tweaked toml for git repo https://github.com/BenSandeen/sudoku-hinter-rs written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/BenSandeen/sudoku-hinter-rs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 382971d9cbcf9742bf3c01efcd05a8d9f5a05969ce484c0efe6b1cc79ce4ee70
[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" "382971d9cbcf9742bf3c01efcd05a8d9f5a05969ce484c0efe6b1cc79ce4ee70", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "382971d9cbcf9742bf3c01efcd05a8d9f5a05969ce484c0efe6b1cc79ce4ee70", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "382971d9cbcf9742bf3c01efcd05a8d9f5a05969ce484c0efe6b1cc79ce4ee70", kill_on_drop: false }`
[INFO] [stdout] 382971d9cbcf9742bf3c01efcd05a8d9f5a05969ce484c0efe6b1cc79ce4ee70
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=warn" "-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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d77fde3681e250f8eeab89c09a3e288f5d420fee5ce0439c74fd65d76d52677d
[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" "d77fde3681e250f8eeab89c09a3e288f5d420fee5ce0439c74fd65d76d52677d", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.38
[INFO] [stderr]    Compiling serde_derive v1.0.115
[INFO] [stderr]    Compiling serde v1.0.115
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling bstr v0.2.13
[INFO] [stderr]    Compiling csv v1.1.3
[INFO] [stderr]    Compiling sudoku-hinter-rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `BorrowMut`
[INFO] [stdout]  --> src/main.rs:5:19
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::borrow::{BorrowMut, Borrow};
[INFO] [stdout]   |                   ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Rem`
[INFO] [stdout]   --> src/main.rs:10:33
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::ops::{Index, IndexMut, Rem};
[INFO] [stdout]    |                                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ii`
[INFO] [stdout]    --> src/main.rs:359:14
[INFO] [stdout]     |
[INFO] [stdout] 359 |         for (ii, row) in self.board.iter().enumerate() {
[INFO] [stdout]     |              ^^ help: if this is intentional, prefix it with an underscore: `_ii`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `jj`
[INFO] [stdout]    --> src/main.rs:361:18
[INFO] [stdout]     |
[INFO] [stdout] 361 |             for (jj, col) in row.iter().enumerate() {
[INFO] [stdout]     |                  ^^ help: if this is intentional, prefix it with an underscore: `_jj`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut rng = rand::thread_rng();
[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: function is never used: `has_unique_elements`
[INFO] [stdout]   --> src/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn has_unique_elements<T>(iter: T) -> bool
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `check_intermediate_puzzle`
[INFO] [stdout]    --> src/main.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 246 |     fn check_intermediate_puzzle(&self, last_modified_cell: Cell) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:360:13
[INFO] [stdout]     |
[INFO] [stdout] 360 |             write!(f, "\n");
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:362:17
[INFO] [stdout]     |
[INFO] [stdout] 362 |                 write!(f, " {} ", *col);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 42.58s
[INFO] running `Command { std: "docker" "inspect" "d77fde3681e250f8eeab89c09a3e288f5d420fee5ce0439c74fd65d76d52677d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d77fde3681e250f8eeab89c09a3e288f5d420fee5ce0439c74fd65d76d52677d", kill_on_drop: false }`
[INFO] [stdout] d77fde3681e250f8eeab89c09a3e288f5d420fee5ce0439c74fd65d76d52677d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=warn" "-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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 13dafdb4f262516151a24ab9c09e7699ca6191cadeb8292861e84810a1b31897
[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" "13dafdb4f262516151a24ab9c09e7699ca6191cadeb8292861e84810a1b31897", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling sudoku-hinter-rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `BorrowMut`
[INFO] [stdout]  --> src/main.rs:5:19
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::borrow::{BorrowMut, Borrow};
[INFO] [stdout]   |                   ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Rem`
[INFO] [stdout]   --> src/main.rs:10:33
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::ops::{Index, IndexMut, Rem};
[INFO] [stdout]    |                                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ii`
[INFO] [stdout]    --> src/main.rs:359:14
[INFO] [stdout]     |
[INFO] [stdout] 359 |         for (ii, row) in self.board.iter().enumerate() {
[INFO] [stdout]     |              ^^ help: if this is intentional, prefix it with an underscore: `_ii`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `jj`
[INFO] [stdout]    --> src/main.rs:361:18
[INFO] [stdout]     |
[INFO] [stdout] 361 |             for (jj, col) in row.iter().enumerate() {
[INFO] [stdout]     |                  ^^ help: if this is intentional, prefix it with an underscore: `_jj`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut rng = rand::thread_rng();
[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: function is never used: `has_unique_elements`
[INFO] [stdout]   --> src/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn has_unique_elements<T>(iter: T) -> bool
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `check_intermediate_puzzle`
[INFO] [stdout]    --> src/main.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 246 |     fn check_intermediate_puzzle(&self, last_modified_cell: Cell) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:360:13
[INFO] [stdout]     |
[INFO] [stdout] 360 |             write!(f, "\n");
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:362:17
[INFO] [stdout]     |
[INFO] [stdout] 362 |                 write!(f, " {} ", *col);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 2.02s
[INFO] running `Command { std: "docker" "inspect" "13dafdb4f262516151a24ab9c09e7699ca6191cadeb8292861e84810a1b31897", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "13dafdb4f262516151a24ab9c09e7699ca6191cadeb8292861e84810a1b31897", kill_on_drop: false }`
[INFO] [stdout] 13dafdb4f262516151a24ab9c09e7699ca6191cadeb8292861e84810a1b31897
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=warn" "-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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] f667b73762653754879d8f837c43ff0ae944b058aa763b428c0e68223dc1f9e5
[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" "f667b73762653754879d8f837c43ff0ae944b058aa763b428c0e68223dc1f9e5", kill_on_drop: false }`
[INFO] [stderr] warning: unused import: `BorrowMut`
[INFO] [stderr]  --> src/main.rs:5:19
[INFO] [stderr]   |
[INFO] [stderr] 5 | use std::borrow::{BorrowMut, Borrow};
[INFO] [stderr]   |                   ^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::io`
[INFO] [stderr]  --> src/main.rs:9:5
[INFO] [stderr]   |
[INFO] [stderr] 9 | use std::io;
[INFO] [stderr]   |     ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Rem`
[INFO] [stderr]   --> src/main.rs:10:33
[INFO] [stderr]    |
[INFO] [stderr] 10 | use std::ops::{Index, IndexMut, Rem};
[INFO] [stderr]    |                                 ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `ii`
[INFO] [stderr]    --> src/main.rs:359:14
[INFO] [stderr]     |
[INFO] [stderr] 359 |         for (ii, row) in self.board.iter().enumerate() {
[INFO] [stderr]     |              ^^ help: if this is intentional, prefix it with an underscore: `_ii`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `jj`
[INFO] [stderr]    --> src/main.rs:361:18
[INFO] [stderr]     |
[INFO] [stderr] 361 |             for (jj, col) in row.iter().enumerate() {
[INFO] [stderr]     |                  ^^ help: if this is intentional, prefix it with an underscore: `_jj`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let mut rng = rand::thread_rng();
[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: function is never used: `has_unique_elements`
[INFO] [stderr]   --> src/main.rs:42:4
[INFO] [stderr]    |
[INFO] [stderr] 42 | fn has_unique_elements<T>(iter: T) -> bool
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `check_intermediate_puzzle`
[INFO] [stderr]    --> src/main.rs:246:8
[INFO] [stderr]     |
[INFO] [stderr] 246 |     fn check_intermediate_puzzle(&self, last_modified_cell: Cell) -> bool {
[INFO] [stderr]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:360:13
[INFO] [stderr]     |
[INFO] [stderr] 360 |             write!(f, "\n");
[INFO] [stderr]     |             ^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:362:17
[INFO] [stderr]     |
[INFO] [stderr] 362 |                 write!(f, " {} ", *col);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: 10 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.12s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/sudoku_hinter_rs-26dc2b3b1e8db3e3
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "f667b73762653754879d8f837c43ff0ae944b058aa763b428c0e68223dc1f9e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f667b73762653754879d8f837c43ff0ae944b058aa763b428c0e68223dc1f9e5", kill_on_drop: false }`
[INFO] [stdout] f667b73762653754879d8f837c43ff0ae944b058aa763b428c0e68223dc1f9e5
