[INFO] cloning repository https://github.com/modulitos/CtCI-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/modulitos/CtCI-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmodulitos%2FCtCI-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmodulitos%2FCtCI-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8bbaa49c3eca43a77cf1a2cea1b6f98071ad2c78
[INFO] checking modulitos/CtCI-rust against master#c5fbcd35a8217a17f6b63a22217ace06cf8f5f02 for pr-86194
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmodulitos%2FCtCI-rust" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/modulitos/CtCI-rust on toolchain c5fbcd35a8217a17f6b63a22217ace06cf8f5f02
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/modulitos/CtCI-rust
[INFO] finished tweaking git repo https://github.com/modulitos/CtCI-rust
[INFO] tweaked toml for git repo https://github.com/modulitos/CtCI-rust written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/modulitos/CtCI-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 31768c42f90a677177ac53889d8df1d871a556b766c8fbb64c0e0d7c0e75f860
[INFO] running `Command { std: "docker" "start" "-a" "31768c42f90a677177ac53889d8df1d871a556b766c8fbb64c0e0d7c0e75f860", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "31768c42f90a677177ac53889d8df1d871a556b766c8fbb64c0e0d7c0e75f860", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31768c42f90a677177ac53889d8df1d871a556b766c8fbb64c0e0d7c0e75f860", kill_on_drop: false }`
[INFO] [stdout] 31768c42f90a677177ac53889d8df1d871a556b766c8fbb64c0e0d7c0e75f860
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7aa1a3693bc0dc2592814d3ded5b9177dbd50f89effed751c9e300f3d527f9bd
[INFO] running `Command { std: "docker" "start" "-a" "7aa1a3693bc0dc2592814d3ded5b9177dbd50f89effed751c9e300f3d527f9bd", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]     Checking ppv-lite86 v0.2.5
[INFO] [stderr]     Checking c2-chacha v0.2.2
[INFO] [stderr]    Compiling aho-corasick v0.7.6
[INFO] [stderr]     Checking getrandom v0.1.7
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]    Compiling regex v1.3.1
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]    Compiling derive_more v0.15.0
[INFO] [stderr]     Checking rust-solutions v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]   --> src/linked_list/second.rs:11:27
[INFO] [stdout]    |
[INFO] [stdout] 11 | pub type Link<T> = Option<(Box<Node<T>>)>;
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashSet`
[INFO] [stdout]  --> src/linked_list/third.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::collections::HashSet;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashSet`
[INFO] [stdout]  --> src/linked_list/fifth.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::collections::HashSet;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Ord`, `Ordering`
[INFO] [stdout]  --> src/graph.rs:1:16
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cmp::{Ord, Ordering};
[INFO] [stdout]   |                ^^^  ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]   --> src/linked_list/second.rs:11:27
[INFO] [stdout]    |
[INFO] [stdout] 11 | pub type Link<T> = Option<(Box<Node<T>>)>;
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::List`
[INFO] [stdout]    --> src/linked_list/second.rs:167:9
[INFO] [stdout]     |
[INFO] [stdout] 167 |     use super::List;
[INFO] [stdout]     |         ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashSet`
[INFO] [stdout]  --> src/linked_list/third.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::collections::HashSet;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashSet`
[INFO] [stdout]  --> src/linked_list/fifth.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::collections::HashSet;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashSet`
[INFO] [stdout]  --> src/linked_list/refcell_singly.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::collections::HashSet;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/stack.rs:115:9
[INFO] [stdout]     |
[INFO] [stdout] 115 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/binary_search_tree.rs:124:9
[INFO] [stdout]     |
[INFO] [stdout] 124 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Ord`, `Ordering`
[INFO] [stdout]  --> src/graph.rs:1:16
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cmp::{Ord, Ordering};
[INFO] [stdout]   |                ^^^  ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/graph.rs:178:9
[INFO] [stdout]     |
[INFO] [stdout] 178 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/binary_tree.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/binary_tree_refcell.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/binary_search_tree_refcell.rs:128:9
[INFO] [stdout]     |
[INFO] [stdout] 128 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/second.rs:67:12
[INFO] [stdout]    |
[INFO] [stdout] 67 |     pub fn new() -> Self {
[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: `into_iter`
[INFO] [stdout]   --> src/linked_list/second.rs:71:12
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]   --> src/linked_list/second.rs:76:12
[INFO] [stdout]    |
[INFO] [stdout] 76 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter_mut`
[INFO] [stdout]   --> src/linked_list/second.rs:84:12
[INFO] [stdout]    |
[INFO] [stdout] 84 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push`
[INFO] [stdout]   --> src/linked_list/second.rs:90:12
[INFO] [stdout]    |
[INFO] [stdout] 90 |     pub fn push(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek`
[INFO] [stdout]    --> src/linked_list/second.rs:119:12
[INFO] [stdout]     |
[INFO] [stdout] 119 |     pub fn peek(&self) -> Option<&T> {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_mut`
[INFO] [stdout]    --> src/linked_list/second.rs:123:12
[INFO] [stdout]     |
[INFO] [stdout] 123 |     pub fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/third.rs:21:12
[INFO] [stdout]    |
[INFO] [stdout] 21 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `append`
[INFO] [stdout]   --> src/linked_list/third.rs:25:12
[INFO] [stdout]    |
[INFO] [stdout] 25 |     pub fn append(&mut self, elem: T) -> Self {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `tail`
[INFO] [stdout]   --> src/linked_list/third.rs:35:12
[INFO] [stdout]    |
[INFO] [stdout] 35 |     pub fn tail(&self) -> Self {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `head`
[INFO] [stdout]   --> src/linked_list/third.rs:40:12
[INFO] [stdout]    |
[INFO] [stdout] 40 |     pub fn head(&self) -> Option<&T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]    --> src/linked_list/third.rs:107:12
[INFO] [stdout]     |
[INFO] [stdout] 107 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/fourth.rs:19:8
[INFO] [stdout]    |
[INFO] [stdout] 19 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/fourth.rs:29:12
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_front`
[INFO] [stdout]   --> src/linked_list/fourth.rs:35:12
[INFO] [stdout]    |
[INFO] [stdout] 35 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_front`
[INFO] [stdout]   --> src/linked_list/fourth.rs:76:12
[INFO] [stdout]    |
[INFO] [stdout] 76 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `prev`
[INFO] [stdout]   --> src/linked_list/brandon.rs:25:5
[INFO] [stdout]    |
[INFO] [stdout] 25 |     prev: Option<NodeRef<T>>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `tail`
[INFO] [stdout]   --> src/linked_list/brandon.rs:39:8
[INFO] [stdout]    |
[INFO] [stdout] 39 |     fn tail(node: &NodeRef<T>) -> Option<NodeRef<T>> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `remove`
[INFO] [stdout]   --> src/linked_list/brandon.rs:46:8
[INFO] [stdout]    |
[INFO] [stdout] 46 |     fn remove(&mut self) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/brandon.rs:64:8
[INFO] [stdout]    |
[INFO] [stdout] 64 |     fn new() -> Self {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `append`
[INFO] [stdout]   --> src/linked_list/brandon.rs:68:8
[INFO] [stdout]    |
[INFO] [stdout] 68 |     fn append(&mut self, new_value: T) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `tail`
[INFO] [stdout]   --> src/linked_list/brandon.rs:85:8
[INFO] [stdout]    |
[INFO] [stdout] 85 |     fn tail(&self) -> Option<NodeRef<T>> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]   --> src/linked_list/brandon.rs:96:8
[INFO] [stdout]    |
[INFO] [stdout] 96 |     fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `list_has_duplicates`
[INFO] [stdout]    --> src/linked_list/brandon.rs:102:8
[INFO] [stdout]     |
[INFO] [stdout] 102 |     fn list_has_duplicates(&self) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `remove_duplicates`
[INFO] [stdout]    --> src/linked_list/brandon.rs:117:8
[INFO] [stdout]     |
[INFO] [stdout] 117 |     fn remove_duplicates(&mut self) {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]    --> src/linked_list/brandon.rs:228:4
[INFO] [stdout]     |
[INFO] [stdout] 228 | fn main() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/linked_list/fifth.rs:24:12
[INFO] [stdout]    |
[INFO] [stdout] 24 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push`
[INFO] [stdout]   --> src/linked_list/fifth.rs:31:12
[INFO] [stdout]    |
[INFO] [stdout] 31 |     pub fn push(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `pop`
[INFO] [stdout]   --> src/linked_list/fifth.rs:53:12
[INFO] [stdout]    |
[INFO] [stdout] 53 |     pub fn pop(&mut self) -> Option<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 41 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]    --> src/bin/ch3-p3_stack-of-plates.rs:104:9
[INFO] [stdout]     |
[INFO] [stdout] 104 |     use super::*;
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch3_p3_stack_of_plates`
[INFO] [stdout]    --> src/bin/ch3-p3_stack-of-plates.rs:15:1
[INFO] [stdout]     |
[INFO] [stdout] 15  | / use cracking::Stack;
[INFO] [stdout] 16  | | use std::vec::Vec;
[INFO] [stdout] 17  | |
[INFO] [stdout] 18  | | struct SetOfStacks<T> {
[INFO] [stdout] ...   |
[INFO] [stdout] 195 | |     }
[INFO] [stdout] 196 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch3-p3_stack-of-plates.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: cannot borrow `map` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/bin/ch1-p3_check-permutation.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 14 |         if let Some(count) = map.get(&c) {
[INFO] [stdout]    |                              --- immutable borrow occurs here
[INFO] [stdout] 15 |             map.insert(c, count + 1);
[INFO] [stdout]    |             ^^^           ----- immutable borrow later used here
[INFO] [stdout]    |             |
[INFO] [stdout]    |             mutable borrow occurs here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mutable_borrow_reservation_conflict)]` on by default
[INFO] [stdout]    = warning: this borrowing pattern was not meant to be accepted, and may become a hard error in the future
[INFO] [stdout]    = note: for more information, see issue #59159 <https://github.com/rust-lang/rust/issues/59159>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust-solutions`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch5_p6_conversion`
[INFO] [stdout]   --> src/bin/ch5-p6_conversion.rs:7:1
[INFO] [stdout]    |
[INFO] [stdout] 7  | / fn determine_bits_basic(mut n1: u16, mut n2: u16) -> u8 {
[INFO] [stdout] 8  | |     let mut bits = 0;
[INFO] [stdout] 9  | |     while n1 > 0 || n2 > 0 {
[INFO] [stdout] 10 | |         // println!("n1: {:b}", n1);
[INFO] [stdout] ...  |
[INFO] [stdout] 41 | |     assert_eq!(determine_bits(0b11101_u16, 0b01111_u16), 2);
[INFO] [stdout] 42 | | }
[INFO] [stdout]    | |_^ consider adding a `main` function to `src/bin/ch5-p6_conversion.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/bin/ch2-p6_check-palindrome.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     use super::*;
[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/stack.rs:153:13
[INFO] [stdout]     |
[INFO] [stdout] 153 |         let mut s: Stack<u64> = Stack::new();
[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] error[E0601]: `main` function not found in crate `ch5_p8_draw_line`
[INFO] [stdout]    --> src/bin/ch5-p8_draw-line.rs:13:1
[INFO] [stdout]     |
[INFO] [stdout] 13  | / const MAX: u8 = std::u8::MAX;
[INFO] [stdout] 14  | | use std::convert::TryFrom;
[INFO] [stdout] 15  | |
[INFO] [stdout] 16  | | // draws a line from (x1, x2) (inclusive), at row y.
[INFO] [stdout] ...   |
[INFO] [stdout] 195 | |     assert_eq!(screen, screen_result);
[INFO] [stdout] 196 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch5-p8_draw-line.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `is_rotation`
[INFO] [stdout]   --> src/bin/ch1-p9_string-rotation.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn is_rotation(s1: &str, s2: &str) -> bool {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch5_p3_flip_bit_to_win`
[INFO] [stdout]   --> src/bin/ch5-p3_flip-bit-to-win.rs:8:1
[INFO] [stdout]    |
[INFO] [stdout] 8  | / use std::cmp;
[INFO] [stdout] 9  | |
[INFO] [stdout] 10 | | // This is O(b) time and space complexity, where b is the length of
[INFO] [stdout] 11 | | // the binary representation.
[INFO] [stdout] ...  |
[INFO] [stdout] 72 | |     assert_eq!(flip_to_win(0b101110011), 5);
[INFO] [stdout] 73 | | }
[INFO] [stdout]    | |_^ consider adding a `main` function to `src/bin/ch5-p3_flip-bit-to-win.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch7_p6_jigsaw`
[INFO] [stdout]    --> src/bin/ch7-p6_jigsaw.rs:6:1
[INFO] [stdout]     |
[INFO] [stdout] 6   | / use rand::distributions::Uniform;
[INFO] [stdout] 7   | | use rand::prelude::*;
[INFO] [stdout] 8   | | use std::cmp::PartialEq;
[INFO] [stdout] 9   | | use std::collections::HashMap;
[INFO] [stdout] ...   |
[INFO] [stdout] 441 | |     assert_eq!(p, solved);
[INFO] [stdout] 442 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch7-p6_jigsaw.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: cannot borrow `map` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/bin/ch1-p4_palindrom-permutation.rs:31:13
[INFO] [stdout]    |
[INFO] [stdout] 30 |         if let Some(value) = map.get(&c) {
[INFO] [stdout]    |                              --- immutable borrow occurs here
[INFO] [stdout] 31 |             map.insert(c, value + 1);
[INFO] [stdout]    |             ^^^           ----- immutable borrow later used here
[INFO] [stdout]    |             |
[INFO] [stdout]    |             mutable borrow occurs here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mutable_borrow_reservation_conflict)]` on by default
[INFO] [stdout]    = warning: this borrowing pattern was not meant to be accepted, and may become a hard error in the future
[INFO] [stdout]    = note: for more information, see issue #59159 <https://github.com/rust-lang/rust/issues/59159>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/bin/ch4-p9_bst-sequences.rs:95:9
[INFO] [stdout]    |
[INFO] [stdout] 95 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch4_p9_bst_sequences`
[INFO] [stdout]    --> src/bin/ch4-p9_bst-sequences.rs:19:1
[INFO] [stdout]     |
[INFO] [stdout] 19  | / use cracking::{BinarySearchTree, Tree};
[INFO] [stdout] 20  | | use std::collections::HashSet;
[INFO] [stdout] 21  | |
[INFO] [stdout] 22  | | fn get_all_arrays<T>(bst: BinarySearchTree<T>) -> HashSet<Vec<T>>
[INFO] [stdout] ...   |
[INFO] [stdout] 252 | |     }
[INFO] [stdout] 253 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch4-p9_bst-sequences.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `urlify_2`
[INFO] [stdout]   --> src/bin/ch1-p2_urlify.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn urlify_2(url: &str) -> String {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `determine_bits_basic`
[INFO] [stdout]  --> src/bin/ch5-p6_conversion.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn determine_bits_basic(mut n1: u16, mut n2: u16) -> u8 {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Node`
[INFO] [stdout]   --> src/bin/ch2-p7_check-intersection.rs:11:48
[INFO] [stdout]    |
[INFO] [stdout] 11 | use cracking::{SinglyLinkedList as LinkedList, Node};
[INFO] [stdout]    |                                                ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cell::RefCell`
[INFO] [stdout]   --> src/bin/ch2-p7_check-intersection.rs:14:5
[INFO] [stdout]    |
[INFO] [stdout] 14 | use std::cell::RefCell;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/bin/ch2-p7_check-intersection.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch2_p7_check_intersection`
[INFO] [stdout]    --> src/bin/ch2-p7_check-intersection.rs:10:1
[INFO] [stdout]     |
[INFO] [stdout] 10  | / extern crate cracking;
[INFO] [stdout] 11  | | use cracking::{SinglyLinkedList as LinkedList, Node};
[INFO] [stdout] 12  | |
[INFO] [stdout] 13  | | use std::rc::Rc;
[INFO] [stdout] ...   |
[INFO] [stdout] 145 | |     }
[INFO] [stdout] 146 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch2-p7_check-intersection.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/bin/ch4-p3_list-of-depths.rs:67:9
[INFO] [stdout]    |
[INFO] [stdout] 67 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch4_p3_list_of_depths`
[INFO] [stdout]    --> src/bin/ch4-p3_list-of-depths.rs:5:1
[INFO] [stdout]     |
[INFO] [stdout] 5   | / use cracking::{BinarySearchTree, Tree};
[INFO] [stdout] 6   | |
[INFO] [stdout] 7   | | trait ListOfDepths<T> {
[INFO] [stdout] 8   | |     fn get_lists(&self) -> Vec<Vec<T>>;
[INFO] [stdout] ...   |
[INFO] [stdout] 167 | |     }
[INFO] [stdout] 168 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch4-p3_list-of-depths.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch3_p5_sort_stack`
[INFO] [stdout]    --> src/bin/ch3-p5_sort-stack.rs:7:1
[INFO] [stdout]     |
[INFO] [stdout] 7   | / extern crate cracking;
[INFO] [stdout] 8   | | use cracking::Stack;
[INFO] [stdout] 9   | |
[INFO] [stdout] 10  | | pub trait SortStack<T> {
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |     }
[INFO] [stdout] 112 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch3-p5_sort-stack.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/bin/ch3-p1_three-in-one.rs:89:13
[INFO] [stdout]    |
[INFO] [stdout] 89 |         let a: ThreeStacks<u64> = ThreeStacks::new();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `grow`
[INFO] [stdout]   --> src/bin/ch3-p1_three-in-one.rs:70:8
[INFO] [stdout]    |
[INFO] [stdout] 70 |     fn grow(&mut self, min_cap: usize) {
[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: `list_has_duplicates`
[INFO] [stdout]    --> src/linked_list/brandon.rs:102:8
[INFO] [stdout]     |
[INFO] [stdout] 102 |     fn list_has_duplicates(&self) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]    --> src/linked_list/brandon.rs:228:4
[INFO] [stdout]     |
[INFO] [stdout] 228 | fn main() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/bin/ch4-p7_build-order.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:129:9
[INFO] [stdout]     |
[INFO] [stdout] 129 |         s.push(1, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:136:9
[INFO] [stdout]     |
[INFO] [stdout] 136 |         s.push(1, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:137:9
[INFO] [stdout]     |
[INFO] [stdout] 137 |         s.push(2, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `urlify_2`
[INFO] [stdout]   --> src/bin/ch1-p2_urlify.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn urlify_2(url: &str) -> String {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |         s.push(3, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:144:9
[INFO] [stdout]     |
[INFO] [stdout] 144 |         s.push(1, 1).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:145:9
[INFO] [stdout]     |
[INFO] [stdout] 145 |         s.push(2, 1).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:146:9
[INFO] [stdout]     |
[INFO] [stdout] 146 |         s.push(3, 1).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:152:9
[INFO] [stdout]     |
[INFO] [stdout] 152 |         s.push(1, 2).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:153:9
[INFO] [stdout]     |
[INFO] [stdout] 153 |         s.push(2, 2).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:154:9
[INFO] [stdout]     |
[INFO] [stdout] 154 |         s.push(3, 2).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:165:9
[INFO] [stdout]     |
[INFO] [stdout] 165 |         s.push(1, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:166:9
[INFO] [stdout]     |
[INFO] [stdout] 166 |         s.push(2, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_ok` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:167:9
[INFO] [stdout]     |
[INFO] [stdout] 167 |         s.push(3, 0).is_ok();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is ok, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_err` that must be used
[INFO] [stdout]    --> src/bin/ch3-p1_three-in-one.rs:168:9
[INFO] [stdout]     |
[INFO] [stdout] 168 |         s.push(4, 0).is_err();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you intended to assert that this is err, consider `.unwrap_err()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `ch4_p7_build_order`
[INFO] [stdout]    --> src/bin/ch4-p7_build-order.rs:20:1
[INFO] [stdout]     |
[INFO] [stdout] 20  | / use cracking::{Graph, IntoChar};
[INFO] [stdout] 21  | | use std::collections::HashSet;
[INFO] [stdout] 22  | | use std::iter::FromIterator;
[INFO] [stdout] 23  | |
[INFO] [stdout] ...   |
[INFO] [stdout] 139 | |     }
[INFO] [stdout] 140 | | }
[INFO] [stdout]     | |_^ consider adding a `main` function to `src/bin/ch4-p7_build-order.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 16 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `from`
[INFO] [stdout]   --> src/bin/ch7-p2_call-center.rs:43:5
[INFO] [stdout]    |
[INFO] [stdout] 43 |     from: String,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "7aa1a3693bc0dc2592814d3ded5b9177dbd50f89effed751c9e300f3d527f9bd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7aa1a3693bc0dc2592814d3ded5b9177dbd50f89effed751c9e300f3d527f9bd", kill_on_drop: false }`
[INFO] [stdout] 7aa1a3693bc0dc2592814d3ded5b9177dbd50f89effed751c9e300f3d527f9bd