[INFO] cloning repository https://github.com/JDemler/BidirectionalTypechecking
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/JDemler/BidirectionalTypechecking" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJDemler%2FBidirectionalTypechecking", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJDemler%2FBidirectionalTypechecking'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1ca2a40121addb09df18c5b0191b23c47abc9456
[INFO] checking JDemler/BidirectionalTypechecking/1ca2a40121addb09df18c5b0191b23c47abc9456 against master#bca37a20bd376ce3fd138e7cdee7fe704e0f8814 for pr-150727
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJDemler%2FBidirectionalTypechecking" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/JDemler/BidirectionalTypechecking
[INFO] finished tweaking git repo https://github.com/JDemler/BidirectionalTypechecking
[INFO] tweaked toml for git repo https://github.com/JDemler/BidirectionalTypechecking written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/JDemler/BidirectionalTypechecking on toolchain bca37a20bd376ce3fd138e7cdee7fe704e0f8814
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/JDemler/BidirectionalTypechecking 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" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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:aa71247004a7fa38d13ec170f48f06cdedf5bc50b2a8645e56ed7e992e6fa513" "/opt/rustwide/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 057ee0f2ecf8616115232f5adc94d2ee2e5b514ab729915d1a2e3bef874eb6c6
[INFO] running `Command { std: "docker" "start" "-a" "057ee0f2ecf8616115232f5adc94d2ee2e5b514ab729915d1a2e3bef874eb6c6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "057ee0f2ecf8616115232f5adc94d2ee2e5b514ab729915d1a2e3bef874eb6c6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "057ee0f2ecf8616115232f5adc94d2ee2e5b514ab729915d1a2e3bef874eb6c6", kill_on_drop: false }`
[INFO] [stdout] 057ee0f2ecf8616115232f5adc94d2ee2e5b514ab729915d1a2e3bef874eb6c6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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:aa71247004a7fa38d13ec170f48f06cdedf5bc50b2a8645e56ed7e992e6fa513" "/opt/rustwide/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8f7f6da6a3b523b2d21adbd9f8dc60d8143843fb0aeee6818ab748cc0173ecf1
[INFO] running `Command { std: "docker" "start" "-a" "8f7f6da6a3b523b2d21adbd9f8dc60d8143843fb0aeee6818ab748cc0173ecf1", kill_on_drop: false }`
[INFO] [stderr]     Checking bidirectional_typeinference v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `right_context`
[INFO] [stdout]    --> src/main.rs:591:24
[INFO] [stdout]     |
[INFO] [stdout] 591 |     let (left_context, right_context) =
[INFO] [stdout]     |                        ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_right_context`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `right_context`
[INFO] [stdout]    --> src/main.rs:655:24
[INFO] [stdout]     |
[INFO] [stdout] 655 |     let (left_context, right_context) =
[INFO] [stdout]     |                        ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_right_context`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Expression` is never used
[INFO] [stdout]   --> src/main.rs:14:6
[INFO] [stdout]    |
[INFO] [stdout] 14 | enum Expression {
[INFO] [stdout]    |      ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Literal` is never used
[INFO] [stdout]   --> src/main.rs:39:6
[INFO] [stdout]    |
[INFO] [stdout] 39 | enum Literal {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Type` is never used
[INFO] [stdout]   --> src/main.rs:63:6
[INFO] [stdout]    |
[INFO] [stdout] 63 | enum Type {
[INFO] [stdout]    |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `LiteralType` is never used
[INFO] [stdout]   --> src/main.rs:86:6
[INFO] [stdout]    |
[INFO] [stdout] 86 | enum LiteralType {
[INFO] [stdout]    |      ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `is_monotype` is never used
[INFO] [stdout]    --> src/main.rs:109:8
[INFO] [stdout]     |
[INFO] [stdout] 108 | impl Type {
[INFO] [stdout]     | --------- method in this implementation
[INFO] [stdout] 109 |     fn is_monotype(&self) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `ContextElement` is never used
[INFO] [stdout]    --> src/main.rs:119:6
[INFO] [stdout]     |
[INFO] [stdout] 119 | enum ContextElement {
[INFO] [stdout]     |      ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Context` is never constructed
[INFO] [stdout]    --> src/main.rs:141:8
[INFO] [stdout]     |
[INFO] [stdout] 141 | struct Context {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: multiple associated items are never used
[INFO] [stdout]    --> src/main.rs:161:8
[INFO] [stdout]     |
[INFO] [stdout] 160 | impl Context {
[INFO] [stdout]     | ------------ associated items in this implementation
[INFO] [stdout] 161 |     fn initial() -> Self {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 167 |     fn add(&self, element: ContextElement) -> Self {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] ...
[INFO] [stdout] 173 |     fn split_at(&self, element: ContextElement) -> (Context, Context) {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 188 |     fn insert_in_place(&self, element: ContextElement, inserts: Vec<ContextElement>) -> Self {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 197 |     fn drop(&self, element: ContextElement) -> Self {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 206 |     fn get_solved(&self, alpha: &str) -> Option<&Type> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 217 |     fn has_existential(&self, alpha: &str) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 223 |     fn has_variable(&self, alpha: &str) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 229 |     fn get_annotation(&self, x: &str) -> Option<&Type> {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `State` is never constructed
[INFO] [stdout]    --> src/main.rs:245:8
[INFO] [stdout]     |
[INFO] [stdout] 245 | struct State {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `initial` and `fresh_existential` are never used
[INFO] [stdout]    --> src/main.rs:250:8
[INFO] [stdout]     |
[INFO] [stdout] 249 | impl State {
[INFO] [stdout]     | ---------- associated items in this implementation
[INFO] [stdout] 250 |     fn initial() -> State {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 254 |     fn fresh_existential(&mut self) -> String {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `literal_checks_against` is never used
[INFO] [stdout]    --> src/main.rs:261:4
[INFO] [stdout]     |
[INFO] [stdout] 261 | fn literal_checks_against(literal: &Literal, type_: &LiteralType) -> bool {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `checks_against` is never used
[INFO] [stdout]    --> src/main.rs:274:4
[INFO] [stdout]     |
[INFO] [stdout] 274 | fn checks_against(
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `literal_synthesizes_to` is never used
[INFO] [stdout]    --> src/main.rs:323:4
[INFO] [stdout]     |
[INFO] [stdout] 323 | fn literal_synthesizes_to(literal: &Literal) -> LiteralType {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `synthesizes_to` is never used
[INFO] [stdout]    --> src/main.rs:335:4
[INFO] [stdout]     |
[INFO] [stdout] 335 | fn synthesizes_to(state: &mut State, context: &Context, expr: &Expression) -> (Type, Context) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `application_synthesizes_to` is never used
[INFO] [stdout]    --> src/main.rs:411:4
[INFO] [stdout]     |
[INFO] [stdout] 411 | fn application_synthesizes_to(
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `is_well_formed` is never used
[INFO] [stdout]    --> src/main.rs:465:4
[INFO] [stdout]     |
[INFO] [stdout] 465 | fn is_well_formed(context: &Context, type_: &Type) -> bool {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `occurs_in` is never used
[INFO] [stdout]    --> src/main.rs:483:4
[INFO] [stdout]     |
[INFO] [stdout] 483 | fn occurs_in(alpha: &str, a: &Type) -> bool {
[INFO] [stdout]     |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `subtype` is never used
[INFO] [stdout]    --> src/main.rs:501:4
[INFO] [stdout]     |
[INFO] [stdout] 501 | fn subtype(state: &mut State, context: &Context, a: &Type, b: &Type) -> Context {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `instantiate_l` is never used
[INFO] [stdout]    --> src/main.rs:589:4
[INFO] [stdout]     |
[INFO] [stdout] 589 | fn instantiate_l(state: &mut State, context: &Context, alpha: &str, b: &Type) -> Context {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `instantiate_r` is never used
[INFO] [stdout]    --> src/main.rs:653:4
[INFO] [stdout]     |
[INFO] [stdout] 653 | fn instantiate_r(state: &mut State, context: &Context, a: &Type, alpha: &str) -> Context {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `apply_context` is never used
[INFO] [stdout]    --> src/main.rs:743:4
[INFO] [stdout]     |
[INFO] [stdout] 743 | fn apply_context(a: Type, context: &Context) -> Type {
[INFO] [stdout]     |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `substitution` is never used
[INFO] [stdout]    --> src/main.rs:773:4
[INFO] [stdout]     |
[INFO] [stdout] 773 | fn substitution(a: &Type, alpha: &str, b: &Type) -> Type {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `synth` is never used
[INFO] [stdout]    --> src/main.rs:808:4
[INFO] [stdout]     |
[INFO] [stdout] 808 | fn synth(expression: Expression) -> Type {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_helper` is never used
[INFO] [stdout]    --> src/main.rs:819:4
[INFO] [stdout]     |
[INFO] [stdout] 819 | fn print_helper(fun: &str, c1: String, c2: String, context: &Context) {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `print_rule` is never used
[INFO] [stdout]    --> src/main.rs:829:4
[INFO] [stdout]     |
[INFO] [stdout] 829 | fn print_rule(rule: &str) {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `literal_string` is never used
[INFO] [stdout]    --> src/main.rs:833:4
[INFO] [stdout]     |
[INFO] [stdout] 833 | fn literal_string() -> Expression {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `literal_bool` is never used
[INFO] [stdout]    --> src/main.rs:837:4
[INFO] [stdout]     |
[INFO] [stdout] 837 | fn literal_bool() -> Expression {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `construct_app` is never used
[INFO] [stdout]     --> src/main.rs:1024:4
[INFO] [stdout]      |
[INFO] [stdout] 1024 | fn construct_app(e0: Expression, e1: Expression) -> Expression {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `construct_let` is never used
[INFO] [stdout]     --> src/main.rs:1028:4
[INFO] [stdout]      |
[INFO] [stdout] 1028 | fn construct_let(var: &str, e0: Expression, body: Expression) -> Expression {
[INFO] [stdout]      |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `id_fn` is never used
[INFO] [stdout]     --> src/main.rs:1032:4
[INFO] [stdout]      |
[INFO] [stdout] 1032 | fn id_fn() -> Expression {
[INFO] [stdout]      |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 | /         &self.elements.iter().fold(true, |first, ele| {
[INFO] [stdout] 149 | |             if !first {
[INFO] [stdout] 150 | |                 write!(f, ", ").unwrap()
[INFO] [stdout] 151 | |             };
[INFO] [stdout] 152 | |             write!(f, "{}", ele).unwrap();
[INFO] [stdout] 153 | |             false
[INFO] [stdout] 154 | |         });
[INFO] [stdout]     | |__________^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 148 |         let _ = &self.elements.iter().fold(true, |first, ele| {
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Vec::<T, A>::split_off` that must be used
[INFO] [stdout]    --> src/main.rs:200:13
[INFO] [stdout]     |
[INFO] [stdout] 200 |             eles.split_off(index);
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: use `.truncate()` if you don't need the other half
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 200 |             let _ = eles.split_off(index);
[INFO] [stdout]     |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `right_context`
[INFO] [stdout]    --> src/main.rs:591:24
[INFO] [stdout]     |
[INFO] [stdout] 591 |     let (left_context, right_context) =
[INFO] [stdout]     |                        ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_right_context`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `right_context`
[INFO] [stdout]    --> src/main.rs:655:24
[INFO] [stdout]     |
[INFO] [stdout] 655 |     let (left_context, right_context) =
[INFO] [stdout]     |                        ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_right_context`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Char`, `Int`, `Float`, and `Unit` are never constructed
[INFO] [stdout]   --> src/main.rs:40:5
[INFO] [stdout]    |
[INFO] [stdout] 39 | enum Literal {
[INFO] [stdout]    |      ------- variants in this enum
[INFO] [stdout] 40 |     Char(char),
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 41 |     String(String),
[INFO] [stdout] 42 |     Int(isize),
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 43 |     Float(f64),
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 44 |     Bool(bool),
[INFO] [stdout] 45 |     Unit,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `Literal` has derived impls for the traits `Debug` and `Clone`, but these are 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: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 | /         &self.elements.iter().fold(true, |first, ele| {
[INFO] [stdout] 149 | |             if !first {
[INFO] [stdout] 150 | |                 write!(f, ", ").unwrap()
[INFO] [stdout] 151 | |             };
[INFO] [stdout] 152 | |             write!(f, "{}", ele).unwrap();
[INFO] [stdout] 153 | |             false
[INFO] [stdout] 154 | |         });
[INFO] [stdout]     | |__________^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 148 |         let _ = &self.elements.iter().fold(true, |first, ele| {
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Vec::<T, A>::split_off` that must be used
[INFO] [stdout]    --> src/main.rs:200:13
[INFO] [stdout]     |
[INFO] [stdout] 200 |             eles.split_off(index);
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: use `.truncate()` if you don't need the other half
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 200 |             let _ = eles.split_off(index);
[INFO] [stdout]     |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.41s
[INFO] running `Command { std: "docker" "inspect" "8f7f6da6a3b523b2d21adbd9f8dc60d8143843fb0aeee6818ab748cc0173ecf1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8f7f6da6a3b523b2d21adbd9f8dc60d8143843fb0aeee6818ab748cc0173ecf1", kill_on_drop: false }`
[INFO] [stdout] 8f7f6da6a3b523b2d21adbd9f8dc60d8143843fb0aeee6818ab748cc0173ecf1
