[INFO] cloning repository https://github.com/joshuacox1/exact-cover
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/joshuacox1/exact-cover" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjoshuacox1%2Fexact-cover", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjoshuacox1%2Fexact-cover'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0f435891e004c4cf6aba04ac7353e45601b68545
[INFO] checking joshuacox1/exact-cover against try#7424ce9ff9baac3e9d9f5dd3c85828cddea0134d for pr-136776-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjoshuacox1%2Fexact-cover" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/joshuacox1/exact-cover
[INFO] finished tweaking git repo https://github.com/joshuacox1/exact-cover
[INFO] tweaked toml for git repo https://github.com/joshuacox1/exact-cover written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/joshuacox1/exact-cover on toolchain 7424ce9ff9baac3e9d9f5dd3c85828cddea0134d
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/joshuacox1/exact-cover already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "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
[ERROR] error running command: no output for 300 seconds
[INFO] checking joshuacox1/exact-cover against try#7424ce9ff9baac3e9d9f5dd3c85828cddea0134d for pr-136776-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjoshuacox1%2Fexact-cover" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/joshuacox1/exact-cover
[INFO] finished tweaking git repo https://github.com/joshuacox1/exact-cover
[INFO] tweaked toml for git repo https://github.com/joshuacox1/exact-cover written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/joshuacox1/exact-cover on toolchain 7424ce9ff9baac3e9d9f5dd3c85828cddea0134d
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/joshuacox1/exact-cover already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "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-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0b53616ae8d35a60f4e8fe4555d321ae375e10678c969e22c6eeb152a5e068e5
[INFO] running `Command { std: "docker" "start" "-a" "0b53616ae8d35a60f4e8fe4555d321ae375e10678c969e22c6eeb152a5e068e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0b53616ae8d35a60f4e8fe4555d321ae375e10678c969e22c6eeb152a5e068e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0b53616ae8d35a60f4e8fe4555d321ae375e10678c969e22c6eeb152a5e068e5", kill_on_drop: false }`
[INFO] [stdout] 0b53616ae8d35a60f4e8fe4555d321ae375e10678c969e22c6eeb152a5e068e5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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" "RUSTDOCFLAGS=--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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+7424ce9ff9baac3e9d9f5dd3c85828cddea0134d" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7b6390320a8f5ee9e91f1b3cd1ad423b24f1726c224b8ab0cc165a2b5449eeda
[INFO] running `Command { std: "docker" "start" "-a" "7b6390320a8f5ee9e91f1b3cd1ad423b24f1726c224b8ab0cc165a2b5449eeda", kill_on_drop: false }`
[INFO] [stderr]     Checking bumpalo v3.19.0
[INFO] [stderr]     Checking exact_cover_solver v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `ExactCoverSolver`
[INFO] [stdout]  --> src/solver/representable.rs:2:17
[INFO] [stdout]   |
[INFO] [stdout] 2 |     ExactCover, ExactCoverSolver, ExactCoverProblem, PartialCover
[INFO] [stdout]   |                 ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `arrayvec::ArrayVec`
[INFO] [stdout]  --> src/solver/solver.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use arrayvec::ArrayVec;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `itertools::Itertools`
[INFO] [stdout]  --> src/solver/solver.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use itertools::Itertools;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `ENTRY_IDX` should have an upper camel case name
[INFO] [stdout]   --> src/solver/solver.rs:83:6
[INFO] [stdout]    |
[INFO] [stdout] 83 | type ENTRY_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to upper camel case: `EntryIdx`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_camel_case_types)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `COL_OR_ROW_IDX` should have an upper camel case name
[INFO] [stdout]   --> src/solver/solver.rs:84:6
[INFO] [stdout]    |
[INFO] [stdout] 84 | type COL_OR_ROW_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^ help: convert the identifier to upper camel case: `ColOrRowIdx`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ExactCoverProblemError` and `SparseBinaryMatrix`
[INFO] [stdout]   --> src/solver/mod.rs:12:38
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub use problem::{ExactCoverProblem, ExactCoverProblemError,
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 13 | SparseBinaryMatrix};
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `ExactCoverSolver`
[INFO] [stdout]  --> src/problems/n_queens.rs:7:21
[INFO] [stdout]   |
[INFO] [stdout] 7 |         ExactCover, ExactCoverSolver, ExactCoverProblem, PartialCover,
[INFO] [stdout]   |                     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `ExactCoverSolver`
[INFO] [stdout]  --> src/solver/representable.rs:2:17
[INFO] [stdout]   |
[INFO] [stdout] 2 |     ExactCover, ExactCoverSolver, ExactCoverProblem, PartialCover
[INFO] [stdout]   |                 ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `arrayvec::ArrayVec`
[INFO] [stdout]  --> src/solver/solver.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use arrayvec::ArrayVec;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `itertools::Itertools`
[INFO] [stdout]  --> src/solver/solver.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use itertools::Itertools;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `ENTRY_IDX` should have an upper camel case name
[INFO] [stdout]   --> src/solver/solver.rs:83:6
[INFO] [stdout]    |
[INFO] [stdout] 83 | type ENTRY_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to upper camel case: `EntryIdx`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_camel_case_types)]` (part of `#[warn(nonstandard_style)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type `COL_OR_ROW_IDX` should have an upper camel case name
[INFO] [stdout]   --> src/solver/solver.rs:84:6
[INFO] [stdout]    |
[INFO] [stdout] 84 | type COL_OR_ROW_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^ help: convert the identifier to upper camel case: `ColOrRowIdx`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ExactCoverRepresentable` and `problems::NQueens`
[INFO] [stdout]  --> src/solver/tests/cases.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     problems::NQueens,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 8 |     solver::{ExactCover, ExactCoverSolver, ExactCoverRepresentable,
[INFO] [stdout]   |                                            ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `ExactCoverProblemError`
[INFO] [stdout]   --> src/solver/mod.rs:12:38
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub use problem::{ExactCoverProblem, ExactCoverProblemError,
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `o_rows` and `empty_rows` are never read
[INFO] [stdout]   --> src/solver/solver.rs:59:5
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub struct ExactCoverSolver {
[INFO] [stdout]    |            ---------------- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 59 |     o_rows: Vec<usize>,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 64 |     empty_rows: Vec<usize>,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `ExactCoverSolver` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_COLS` is never used
[INFO] [stdout]   --> src/solver/solver.rs:73:7
[INFO] [stdout]    |
[INFO] [stdout] 73 | const MAX_COLS: usize = 4096;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_ROWS` is never used
[INFO] [stdout]   --> src/solver/solver.rs:74:7
[INFO] [stdout]    |
[INFO] [stdout] 74 | const MAX_ROWS: usize = 4096;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_ONES` is never used
[INFO] [stdout]   --> src/solver/solver.rs:75:7
[INFO] [stdout]    |
[INFO] [stdout] 75 | const MAX_ONES: usize = 65536 - MAX_COLS;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `ENTRY_IDX` is never used
[INFO] [stdout]   --> src/solver/solver.rs:83:6
[INFO] [stdout]    |
[INFO] [stdout] 83 | type ENTRY_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `COL_OR_ROW_IDX` is never used
[INFO] [stdout]   --> src/solver/solver.rs:84:6
[INFO] [stdout]    |
[INFO] [stdout] 84 | type COL_OR_ROW_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/solver/solver.rs:346:27
[INFO] [stdout]     |
[INFO] [stdout] 346 |     pub fn iter_solutions(&mut self) -> Solutions {
[INFO] [stdout]     |                           ^^^^^^^^^     ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 346 |     pub fn iter_solutions(&mut self) -> Solutions<'_> {
[INFO] [stdout]     |                                                  ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/solver/solver.rs:351:23
[INFO] [stdout]     |
[INFO] [stdout] 351 |     pub fn iter_steps(&mut self) -> SolverSteps {
[INFO] [stdout]     |                       ^^^^^^^^^     ^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 351 |     pub fn iter_steps(&mut self) -> SolverSteps<'_> {
[INFO] [stdout]     |                                                ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `o_rows` and `empty_rows` are never read
[INFO] [stdout]   --> src/solver/solver.rs:59:5
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub struct ExactCoverSolver {
[INFO] [stdout]    |            ---------------- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 59 |     o_rows: Vec<usize>,
[INFO] [stdout]    |     ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 64 |     empty_rows: Vec<usize>,
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `ExactCoverSolver` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_COLS` is never used
[INFO] [stdout]   --> src/solver/solver.rs:73:7
[INFO] [stdout]    |
[INFO] [stdout] 73 | const MAX_COLS: usize = 4096;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_ROWS` is never used
[INFO] [stdout]   --> src/solver/solver.rs:74:7
[INFO] [stdout]    |
[INFO] [stdout] 74 | const MAX_ROWS: usize = 4096;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `MAX_ONES` is never used
[INFO] [stdout]   --> src/solver/solver.rs:75:7
[INFO] [stdout]    |
[INFO] [stdout] 75 | const MAX_ONES: usize = 65536 - MAX_COLS;
[INFO] [stdout]    |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `ENTRY_IDX` is never used
[INFO] [stdout]   --> src/solver/solver.rs:83:6
[INFO] [stdout]    |
[INFO] [stdout] 83 | type ENTRY_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias `COL_OR_ROW_IDX` is never used
[INFO] [stdout]   --> src/solver/solver.rs:84:6
[INFO] [stdout]    |
[INFO] [stdout] 84 | type COL_OR_ROW_IDX = u16;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/solver/solver.rs:346:27
[INFO] [stdout]     |
[INFO] [stdout] 346 |     pub fn iter_solutions(&mut self) -> Solutions {
[INFO] [stdout]     |                           ^^^^^^^^^     ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 346 |     pub fn iter_solutions(&mut self) -> Solutions<'_> {
[INFO] [stdout]     |                                                  ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/solver/solver.rs:351:23
[INFO] [stdout]     |
[INFO] [stdout] 351 |     pub fn iter_steps(&mut self) -> SolverSteps {
[INFO] [stdout]     |                       ^^^^^^^^^     ^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 351 |     pub fn iter_steps(&mut self) -> SolverSteps<'_> {
[INFO] [stdout]     |                                                ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Duration` and `Instant`
[INFO] [stdout]  --> src/main.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::time::{Duration, Instant};
[INFO] [stdout]   |                 ^^^^^^^^  ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `bumpalo::Bump`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use bumpalo::Bump;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::sleep`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::thread::sleep;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `itertools::Itertools`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use itertools::Itertools;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `SolverStep`
[INFO] [stdout]  --> src/main.rs:8:48
[INFO] [stdout]   |
[INFO] [stdout] 8 |     ExactCoverSolver, ExactCoverRepresentable, SolverStep
[INFO] [stdout]   |                                                ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Duration` and `Instant`
[INFO] [stdout]  --> src/main.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::time::{Duration, Instant};
[INFO] [stdout]   |                 ^^^^^^^^  ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `bumpalo::Bump`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use bumpalo::Bump;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::sleep`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::thread::sleep;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `itertools::Itertools`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use itertools::Itertools;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `SolverStep`
[INFO] [stdout]  --> src/main.rs:8:48
[INFO] [stdout]   |
[INFO] [stdout] 8 |     ExactCoverSolver, ExactCoverRepresentable, SolverStep
[INFO] [stdout]   |                                                ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.49s
[INFO] running `Command { std: "docker" "inspect" "7b6390320a8f5ee9e91f1b3cd1ad423b24f1726c224b8ab0cc165a2b5449eeda", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7b6390320a8f5ee9e91f1b3cd1ad423b24f1726c224b8ab0cc165a2b5449eeda", kill_on_drop: false }`
[INFO] [stdout] 7b6390320a8f5ee9e91f1b3cd1ad423b24f1726c224b8ab0cc165a2b5449eeda