[INFO] cloning repository https://github.com/peaceman/aoc2020
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/peaceman/aoc2020" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpeaceman%2Faoc2020", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpeaceman%2Faoc2020'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4bad951d5199fde73540f1e3aa5bcb223902169e
[INFO] testing peaceman/aoc2020 against 1.59.0 for beta-1.60-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpeaceman%2Faoc2020" "/workspace/builds/worker-28/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-28/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/peaceman/aoc2020 on toolchain 1.59.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/peaceman/aoc2020
[INFO] finished tweaking git repo https://github.com/peaceman/aoc2020
[INFO] tweaked toml for git repo https://github.com/peaceman/aoc2020 written to /workspace/builds/worker-28/source/Cargo.toml
[INFO] crate git repo https://github.com/peaceman/aoc2020 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f9623339d9af263a1e29580e0d2d3e39a39495f93c9dfae179c5bc4fcff8e365
[INFO] running `Command { std: "docker" "start" "-a" "f9623339d9af263a1e29580e0d2d3e39a39495f93c9dfae179c5bc4fcff8e365", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f9623339d9af263a1e29580e0d2d3e39a39495f93c9dfae179c5bc4fcff8e365", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f9623339d9af263a1e29580e0d2d3e39a39495f93c9dfae179c5bc4fcff8e365", kill_on_drop: false }`
[INFO] [stdout] f9623339d9af263a1e29580e0d2d3e39a39495f93c9dfae179c5bc4fcff8e365
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 34c3e83851e65291ab87fa83d809debee9a3deaefa75ce8771337f3ab8bc1f36
[INFO] running `Command { std: "docker" "start" "-a" "34c3e83851e65291ab87fa83d809debee9a3deaefa75ce8771337f3ab8bc1f36", kill_on_drop: false }`
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]    Compiling syn v1.0.53
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling unicode-segmentation v1.7.1
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling hashbrown v0.9.1
[INFO] [stderr]    Compiling unicode-width v0.1.8
[INFO] [stderr]    Compiling regex-syntax v0.6.21
[INFO] [stderr]    Compiling os_str_bytes v2.4.0
[INFO] [stderr]    Compiling termcolor v1.1.2
[INFO] [stderr]    Compiling either v1.6.1
[INFO] [stderr]    Compiling vec_map v0.8.2
[INFO] [stderr]    Compiling strsim v0.10.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling thread_local v1.0.1
[INFO] [stderr]    Compiling textwrap v0.12.1
[INFO] [stderr]    Compiling itertools v0.9.0
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling indexmap v1.6.0
[INFO] [stderr]    Compiling aho-corasick v0.7.15
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling regex v1.4.2
[INFO] [stderr]    Compiling scan_fmt v0.2.5
[INFO] [stderr]    Compiling clap_derive v3.0.0-beta.2
[INFO] [stderr]    Compiling thiserror-impl v1.0.22
[INFO] [stderr]    Compiling thiserror v1.0.22
[INFO] [stderr]    Compiling clap v3.0.0-beta.2
[INFO] [stderr]    Compiling aoc2020 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/bin/day15b.rs:45:6
[INFO] [stdout]    |
[INFO] [stdout] 45 |     };
[INFO] [stdout]    |      ^ help: remove this semicolon
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(redundant_semicolons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around pattern
[INFO] [stdout]   --> src/bin/day14a.rs:70:19
[INFO] [stdout]    |
[INFO] [stdout] 70 |         if let Ok((string_mask)) = scan_fmt!(l, "mask = {}", String) {
[INFO] [stdout]    |                   ^           ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout] 70 -         if let Ok((string_mask)) = scan_fmt!(l, "mask = {}", String) {
[INFO] [stdout] 70 +         if let Ok(string_mask) = scan_fmt!(l, "mask = {}", String) {
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt::Alignment::Left`
[INFO] [stdout]  --> src/bin/day18a.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use core::fmt::Alignment::Left;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::hint::unreachable_unchecked`
[INFO] [stdout]  --> src/bin/day18a.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::hint::unreachable_unchecked;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::Range`
[INFO] [stdout]  --> src/bin/day9a.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::ops::Range;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `birth_year`
[INFO] [stdout]   --> src/bin/day4a.rs:93:5
[INFO] [stdout]    |
[INFO] [stdout] 93 |     birth_year: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `issue_year`
[INFO] [stdout]   --> src/bin/day4a.rs:94:5
[INFO] [stdout]    |
[INFO] [stdout] 94 |     issue_year: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `expiration_year`
[INFO] [stdout]   --> src/bin/day4a.rs:95:5
[INFO] [stdout]    |
[INFO] [stdout] 95 |     expiration_year: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `height`
[INFO] [stdout]   --> src/bin/day4a.rs:96:5
[INFO] [stdout]    |
[INFO] [stdout] 96 |     height: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `hair_color`
[INFO] [stdout]   --> src/bin/day4a.rs:97:5
[INFO] [stdout]    |
[INFO] [stdout] 97 |     hair_color: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `eye_color`
[INFO] [stdout]   --> src/bin/day4a.rs:98:5
[INFO] [stdout]    |
[INFO] [stdout] 98 |     eye_color: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `passport_id`
[INFO] [stdout]   --> src/bin/day4a.rs:99:5
[INFO] [stdout]    |
[INFO] [stdout] 99 |     passport_id: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `country_id`
[INFO] [stdout]    --> src/bin/day4a.rs:100:5
[INFO] [stdout]     |
[INFO] [stdout] 100 |     country_id: Option<String>,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/bin/day15a.rs:43:6
[INFO] [stdout]    |
[INFO] [stdout] 43 |     };
[INFO] [stdout]    |      ^ help: remove this semicolon
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(redundant_semicolons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `HashMap`, `HashSet`
[INFO] [stdout]  --> src/bin/day9b.rs:3:24
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::collections::{HashMap, HashSet};
[INFO] [stdout]   |                        ^^^^^^^  ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::Range`
[INFO] [stdout]  --> src/bin/day9b.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::ops::Range;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: panic message is not a string literal
[INFO] [stdout]    --> src/bin/day18a.rs:175:20
[INFO] [stdout]     |
[INFO] [stdout] 175 |             panic!(error_msg);
[INFO] [stdout]     |                    ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_fmt_panics)]` on by default
[INFO] [stdout]     = note: this usage of panic!() is deprecated; it will be a hard error in Rust 2021
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/panic-macro-consistency.html>
[INFO] [stdout] help: add a "{}" format string to Display the message
[INFO] [stdout]     |
[INFO] [stdout] 175 |             panic!("{}", error_msg);
[INFO] [stdout]     |                    +++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `expand_rule`
[INFO] [stdout]   --> src/bin/day19b.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn expand_rule(rules: &Rules, idx: usize) -> HashSet<String> {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `birth_year`
[INFO] [stdout]   --> src/bin/day4b.rs:97:5
[INFO] [stdout]    |
[INFO] [stdout] 97 |     birth_year: BirthYear,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `issue_year`
[INFO] [stdout]   --> src/bin/day4b.rs:98:5
[INFO] [stdout]    |
[INFO] [stdout] 98 |     issue_year: IssueYear,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `expiration_year`
[INFO] [stdout]   --> src/bin/day4b.rs:99:5
[INFO] [stdout]    |
[INFO] [stdout] 99 |     expiration_year: ExpirationYear,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `height`
[INFO] [stdout]    --> src/bin/day4b.rs:100:5
[INFO] [stdout]     |
[INFO] [stdout] 100 |     height: Height,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `hair_color`
[INFO] [stdout]    --> src/bin/day4b.rs:101:5
[INFO] [stdout]     |
[INFO] [stdout] 101 |     hair_color: HairColor,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `eye_color`
[INFO] [stdout]    --> src/bin/day4b.rs:102:5
[INFO] [stdout]     |
[INFO] [stdout] 102 |     eye_color: EyeColor,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `passport_id`
[INFO] [stdout]    --> src/bin/day4b.rs:103:5
[INFO] [stdout]     |
[INFO] [stdout] 103 |     passport_id: PassportId,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `country_id`
[INFO] [stdout]    --> src/bin/day4b.rs:104:5
[INFO] [stdout]     |
[INFO] [stdout] 104 |     country_id: Option<String>,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Display`
[INFO] [stdout]  --> src/bin/day11a.rs:4:16
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::{Display, Formatter};
[INFO] [stdout]   |                ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt::Alignment::Left`
[INFO] [stdout]  --> src/bin/day18b.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use core::fmt::Alignment::Left;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fmt::Pointer`
[INFO] [stdout]  --> src/bin/day18b.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::Pointer;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::hint::unreachable_unchecked`
[INFO] [stdout]  --> src/bin/day18b.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::hint::unreachable_unchecked;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `HashSet`
[INFO] [stdout]  --> src/bin/day7b.rs:2:33
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::collections::{HashMap, HashSet};
[INFO] [stdout]   |                                 ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/day11a.rs:81:14
[INFO] [stdout]    |
[INFO] [stdout] 81 |     fn parse(mut reader: impl BufRead) -> Result<Self, ParseError> {
[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: panic message is not a string literal
[INFO] [stdout]    --> src/bin/day18b.rs:176:20
[INFO] [stdout]     |
[INFO] [stdout] 176 |             panic!(error_msg);
[INFO] [stdout]     |                    ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_fmt_panics)]` on by default
[INFO] [stdout]     = note: this usage of panic!() is deprecated; it will be a hard error in Rust 2021
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/panic-macro-consistency.html>
[INFO] [stdout] help: add a "{}" format string to Display the message
[INFO] [stdout]     |
[INFO] [stdout] 176 |             panic!("{}", error_msg);
[INFO] [stdout]     |                    +++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Display`
[INFO] [stdout]  --> src/bin/day11b.rs:4:16
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fmt::{Display, Formatter};
[INFO] [stdout]   |                ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::iter::Filter`
[INFO] [stdout]  --> src/bin/day17b.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::iter::Filter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/bin/day16a.rs:82:29
[INFO] [stdout]    |
[INFO] [stdout] 82 | ...                   std::mem::replace(&mut my_ticket, ticket);
[INFO] [stdout]    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cycle`
[INFO] [stdout]    --> src/bin/day17b.rs:179:9
[INFO] [stdout]     |
[INFO] [stdout] 179 |     for cycle in 0..cycles {
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cycle`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `aoc2020`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc --crate-name day16b --edition=2018 src/bin/day16b.rs --error-format=json --json=diagnostic-rendered-ansi,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=172bcddc683028be -C extra-filename=-172bcddc683028be --out-dir /opt/rustwide/target/debug/deps -L dependency=/opt/rustwide/target/debug/deps --extern clap=/opt/rustwide/target/debug/deps/libclap-6fee4a95eb991ac7.rlib --extern itertools=/opt/rustwide/target/debug/deps/libitertools-e278dee975608827.rlib --extern scan_fmt=/opt/rustwide/target/debug/deps/libscan_fmt-b2cdbbbf78c97995.rlib --extern thiserror=/opt/rustwide/target/debug/deps/libthiserror-9f61af0d835520c4.rlib --cap-lints=warn` (signal: 9, SIGKILL: kill)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "34c3e83851e65291ab87fa83d809debee9a3deaefa75ce8771337f3ab8bc1f36", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "34c3e83851e65291ab87fa83d809debee9a3deaefa75ce8771337f3ab8bc1f36", kill_on_drop: false }`
[INFO] [stdout] 34c3e83851e65291ab87fa83d809debee9a3deaefa75ce8771337f3ab8bc1f36