[INFO] fetching crate subway 0.1.2...
[INFO] linting subway-0.1.2 against nightly for clippy-nonminimal_bool-denied
[INFO] extracting crate subway 0.1.2 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate subway 0.1.2
[INFO] finished tweaking crates.io crate subway 0.1.2
[INFO] tweaked toml for crates.io crate subway 0.1.2 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate subway 0.1.2 on toolchain nightly
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+nightly" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+nightly" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 10 packages to latest compatible versions
[INFO] [stderr]       Adding rand v0.5.6 (available: v0.10.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+nightly" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rand v0.5.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+nightly" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8f68da359cbfc7460a163f12eaaa5d0a5cad4bcf87aebef80273fda06065a874
[INFO] running `Command { std: "docker" "start" "-a" "8f68da359cbfc7460a163f12eaaa5d0a5cad4bcf87aebef80273fda06065a874", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8f68da359cbfc7460a163f12eaaa5d0a5cad4bcf87aebef80273fda06065a874", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8f68da359cbfc7460a163f12eaaa5d0a5cad4bcf87aebef80273fda06065a874", kill_on_drop: false }`
[INFO] [stdout] 8f68da359cbfc7460a163f12eaaa5d0a5cad4bcf87aebef80273fda06065a874
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+nightly" "clippy" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2371ab5a9c34063c44beed5c76775e239aa6976d0f3b0549a575fcd2adcfe21f
[INFO] running `Command { std: "docker" "start" "-a" "2371ab5a9c34063c44beed5c76775e239aa6976d0f3b0549a575fcd2adcfe21f", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking subway v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: method `print` is never used
[INFO] [stdout]    --> src/skiplist.rs:574:8
[INFO] [stdout]     |
[INFO] [stdout] 266 | / impl<K, V> SkipList<K, V>
[INFO] [stdout] 267 | | where
[INFO] [stdout] 268 | |     K: Ord + Clone + Display,
[INFO] [stdout] 269 | |     V: Clone,
[INFO] [stdout]     | |_____________- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 574 |       fn print(&self) {
[INFO] [stdout]     |          ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_marker` after checking its variant with `is_some`
[INFO] [stdout]   --> src/skiplist.rs:79:26
[INFO] [stdout]    |
[INFO] [stdout] 78 |         if maybe_marker.is_some() {
[INFO] [stdout]    |         ------------------------- help: try: `if let Some(<item>) = maybe_marker`
[INFO] [stdout] 79 |             let marker = maybe_marker.unwrap();
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout]    = note: `#[warn(clippy::unnecessary_unwrap)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |         return prev;
[INFO] [stdout]     |         ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout]     = note: `#[warn(clippy::needless_return)]` on by default
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 119 -         return prev;
[INFO] [stdout] 119 +         prev
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_prev_head_ref` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:143:41
[INFO] [stdout]     |
[INFO] [stdout] 142 |                 if maybe_prev_head_ref.is_some() {
[INFO] [stdout]     |                 -------------------------------- help: try: `if let Some(<item>) = maybe_prev_head_ref`
[INFO] [stdout] 143 |                     let prev_head_ref = maybe_prev_head_ref.unwrap();
[INFO] [stdout]     |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_next_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:160:37
[INFO] [stdout]     |
[INFO] [stdout] 158 |                 if maybe_next_node.is_some() {
[INFO] [stdout]     |                 ---------------------------- help: try: `if let Some(<item>) = maybe_next_node`
[INFO] [stdout] 159 |                     // handle insert in the middle
[INFO] [stdout] 160 |                     let next_node = maybe_next_node.unwrap();
[INFO] [stdout]     |                                     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:137:9
[INFO] [stdout]     |
[INFO] [stdout] 137 | /         return match maybe_prev_node {
[INFO] [stdout] 138 | |             // insert at head
[INFO] [stdout] 139 | |             None => {
[INFO] [stdout] 140 | |                 let maybe_prev_head_ref: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] ...   |
[INFO] [stdout] 174 | |         };
[INFO] [stdout]     | |_________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 137 ~         match maybe_prev_node {
[INFO] [stdout] 138 +             // insert at head
[INFO] [stdout] 139 +             None => {
[INFO] [stdout] 140 +                 let maybe_prev_head_ref: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] 141 +                     self.head.as_ref().map(Rc::clone);
[INFO] [stdout] 142 +                 if maybe_prev_head_ref.is_some() {
[INFO] [stdout] 143 +                     let prev_head_ref = maybe_prev_head_ref.unwrap();
[INFO] [stdout] 144 +                     let new_head = Rc::new(RefCell::new(Node::new(key, value)));
[INFO] [stdout] 145 +                     new_head.borrow_mut().right = self.head.take();
[INFO] [stdout] 146 +                     self.head = Some(new_head);
[INFO] [stdout] 147 +                     prev_head_ref.borrow_mut().left = self.head.as_ref().map(Rc::downgrade);
[INFO] [stdout] 148 +                 } else {
[INFO] [stdout] 149 +                     self.head = Some(Rc::new(RefCell::new(Node::new(key, value))));
[INFO] [stdout] 150 +                 }
[INFO] [stdout] 151 +                 self.size += 1;
[INFO] [stdout] 152 +                 Rc::clone(self.head.as_ref().unwrap())
[INFO] [stdout] 153 +             }
[INFO] [stdout] 154 +             Some(prev_node) => {
[INFO] [stdout] 155 +                 let maybe_next_node: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] 156 +                     prev_node.borrow().right.as_ref().map(Rc::clone);
[INFO] [stdout] 157 +                 let new_node = Rc::new(RefCell::new(Node::new(key, value)));
[INFO] [stdout] 158 +                 if maybe_next_node.is_some() {
[INFO] [stdout] 159 +                     // handle insert in the middle
[INFO] [stdout] 160 +                     let next_node = maybe_next_node.unwrap();
[INFO] [stdout] 161 +                     next_node.borrow_mut().left = Some(Rc::downgrade(&new_node));
[INFO] [stdout] 162 +                     new_node.borrow_mut().right = prev_node.borrow_mut().right.take();
[INFO] [stdout] 163 +                     new_node.borrow_mut().left = Some(Rc::downgrade(&prev_node));
[INFO] [stdout] 164 +                     prev_node.borrow_mut().right = Some(new_node);
[INFO] [stdout] 165 +                     self.size += 1;
[INFO] [stdout] 166 +                 } else {
[INFO] [stdout] 167 +                     // handle insert at tail
[INFO] [stdout] 168 +                     new_node.borrow_mut().left = Some(Rc::downgrade(&prev_node));
[INFO] [stdout] 169 +                     prev_node.borrow_mut().right = Some(new_node);
[INFO] [stdout] 170 +                     self.size += 1;
[INFO] [stdout] 171 +                 }
[INFO] [stdout] 172 +                 Rc::clone(prev_node.borrow().right.as_ref().unwrap())
[INFO] [stdout] 173 +             }
[INFO] [stdout] 174 ~         }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_next_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:190:29
[INFO] [stdout]     |
[INFO] [stdout] 189 |         if maybe_next_node.is_some() {
[INFO] [stdout]     |         ---------------------------- help: try: `if let Some(<item>) = maybe_next_node`
[INFO] [stdout] 190 |             let next_node = maybe_next_node.unwrap();
[INFO] [stdout]     |                             ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:207:29
[INFO] [stdout]     |
[INFO] [stdout] 206 |         if maybe_node.is_some() {
[INFO] [stdout]     |         ----------------------- help: try: `if let Some(<item>) = &maybe_node`
[INFO] [stdout] 207 |             let to_delete = maybe_node.as_ref().unwrap();
[INFO] [stdout]     |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_prev_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:210:58
[INFO] [stdout]     |
[INFO] [stdout] 209 |             if maybe_prev_node.is_some() {
[INFO] [stdout]     |             ---------------------------- help: try: `if let Some(<item>) = maybe_prev_node`
[INFO] [stdout] 210 |                 let prev_node: Rc<RefCell<Node<K, V>>> = maybe_prev_node.unwrap();
[INFO] [stdout]     |                                                          ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_new_next` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:214:36
[INFO] [stdout]     |
[INFO] [stdout] 213 |                 if maybe_new_next.is_some() {
[INFO] [stdout]     |                 --------------------------- help: try: `if let Some(<item>) = maybe_new_next`
[INFO] [stdout] 214 |                     let new_next = maybe_new_next.unwrap();
[INFO] [stdout]     |                                    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_current` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:238:27
[INFO] [stdout]     |
[INFO] [stdout] 237 |         if maybe_current.is_some() {
[INFO] [stdout]     |         -------------------------- help: try: `if let Some(<item>) = maybe_current`
[INFO] [stdout] 238 |             let current = maybe_current.unwrap();
[INFO] [stdout]     |                           ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: you should consider adding a `Default` implementation for `SkipList<K, V>`
[INFO] [stdout]    --> src/skiplist.rs:279:5
[INFO] [stdout]     |
[INFO] [stdout] 279 | /     pub fn new() -> SkipList<K, V> {
[INFO] [stdout] 280 | |         let levels = vec![Level::new()];
[INFO] [stdout] 281 | |         SkipList { size: 0, levels }
[INFO] [stdout] 282 | |     }
[INFO] [stdout]     | |_____^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#new_without_default
[INFO] [stdout]     = note: `#[warn(clippy::new_without_default)]` on by default
[INFO] [stdout] help: try adding this
[INFO] [stdout]     |
[INFO] [stdout] 266 + impl<K, V> Default for SkipList<K, V>
[INFO] [stdout] 267 + where
[INFO] [stdout] 268 +     K: Ord + Clone + Display,
[INFO] [stdout] 269 +     V: Clone,
[INFO] [stdout] 270 +  {
[INFO] [stdout] 271 +     fn default() -> Self {
[INFO] [stdout] 272 +         Self::new()
[INFO] [stdout] 273 +     }
[INFO] [stdout] 274 + }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: doc list item overindented
[INFO] [stdout]    --> src/skiplist.rs:288:9
[INFO] [stdout]     |
[INFO] [stdout] 288 |     ///             This is also used as the sort key.
[INFO] [stdout]     |         ^^^^^^^^^^^^ help: try using `  ` (2 spaces)
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
[INFO] [stdout]     = note: `#[warn(clippy::doc_overindented_list_items)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: length comparison to zero
[INFO] [stdout]    --> src/skiplist.rs:303:12
[INFO] [stdout]     |
[INFO] [stdout] 303 |         if self.levels.len() > 0 {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!self.levels.is_empty()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stdout]     = note: `#[warn(clippy::len_zero)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
[INFO] [stdout]    --> src/skiplist.rs:307:13
[INFO] [stdout]     |
[INFO] [stdout] 307 | /             match insertion_path.get(0).unwrap() {
[INFO] [stdout] 308 | |                 Insertion::Before => {
[INFO] [stdout] 309 | |                     is_head = true;
[INFO] [stdout] ...   |
[INFO] [stdout] 312 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_match
[INFO] [stdout]     = note: `#[warn(clippy::single_match)]` on by default
[INFO] [stdout] help: try
[INFO] [stdout]     |
[INFO] [stdout] 307 ~             if let Insertion::Before = insertion_path.get(0).unwrap() {
[INFO] [stdout] 308 +                 is_head = true;
[INFO] [stdout] 309 +             }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: accessing first element with `insertion_path.get(0)`
[INFO] [stdout]    --> src/skiplist.rs:307:19
[INFO] [stdout]     |
[INFO] [stdout] 307 |             match insertion_path.get(0).unwrap() {
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^^^ help: try: `insertion_path.first()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#get_first
[INFO] [stdout]     = note: `#[warn(clippy::get_first)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:509:9
[INFO] [stdout]     |
[INFO] [stdout] 509 | /         return match insertion {
[INFO] [stdout] 510 | |             Insertion::Before => {
[INFO] [stdout] 511 | |                 let new_head = self.levels[level].insert(key.clone(), value.clone());
[INFO] [stdout] 512 | |                 Rc::clone(&new_head)
[INFO] [stdout] ...   |
[INFO] [stdout] 519 | |         };
[INFO] [stdout]     | |_________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 509 ~         match insertion {
[INFO] [stdout] 510 +             Insertion::Before => {
[INFO] [stdout] 511 +                 let new_head = self.levels[level].insert(key.clone(), value.clone());
[INFO] [stdout] 512 +                 Rc::clone(&new_head)
[INFO] [stdout] 513 +             }
[INFO] [stdout] 514 +             Insertion::After(node) => {
[INFO] [stdout] 515 +                 let new_node =
[INFO] [stdout] 516 +                     self.levels[level].insert_after(key.clone(), value.clone(), Rc::clone(node));
[INFO] [stdout] 517 +                 Rc::clone(&new_node)
[INFO] [stdout] 518 +             }
[INFO] [stdout] 519 ~         }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `head` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:530:32
[INFO] [stdout]     |
[INFO] [stdout] 529 |             if head.is_some() {
[INFO] [stdout]     |             ----------------- help: try: `if let Some(<item>) = head`
[INFO] [stdout] 530 |                 let head_ref = head.unwrap();
[INFO] [stdout]     |                                ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:571:9
[INFO] [stdout]     |
[INFO] [stdout] 571 |         return random > 0.50;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 571 -         return random > 0.50;
[INFO] [stdout] 571 +         random > 0.50
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `print` is never used
[INFO] [stdout]    --> src/skiplist.rs:574:8
[INFO] [stdout]     |
[INFO] [stdout] 266 | / impl<K, V> SkipList<K, V>
[INFO] [stdout] 267 | | where
[INFO] [stdout] 268 | |     K: Ord + Clone + Display,
[INFO] [stdout] 269 | |     V: Clone,
[INFO] [stdout]     | |_____________- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 574 |       fn print(&self) {
[INFO] [stdout]     |          ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_marker` after checking its variant with `is_some`
[INFO] [stdout]   --> src/skiplist.rs:79:26
[INFO] [stdout]    |
[INFO] [stdout] 78 |         if maybe_marker.is_some() {
[INFO] [stdout]    |         ------------------------- help: try: `if let Some(<item>) = maybe_marker`
[INFO] [stdout] 79 |             let marker = maybe_marker.unwrap();
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout]    = note: `#[warn(clippy::unnecessary_unwrap)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:119:9
[INFO] [stdout]     |
[INFO] [stdout] 119 |         return prev;
[INFO] [stdout]     |         ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout]     = note: `#[warn(clippy::needless_return)]` on by default
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 119 -         return prev;
[INFO] [stdout] 119 +         prev
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_prev_head_ref` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:143:41
[INFO] [stdout]     |
[INFO] [stdout] 142 |                 if maybe_prev_head_ref.is_some() {
[INFO] [stdout]     |                 -------------------------------- help: try: `if let Some(<item>) = maybe_prev_head_ref`
[INFO] [stdout] 143 |                     let prev_head_ref = maybe_prev_head_ref.unwrap();
[INFO] [stdout]     |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_next_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:160:37
[INFO] [stdout]     |
[INFO] [stdout] 158 |                 if maybe_next_node.is_some() {
[INFO] [stdout]     |                 ---------------------------- help: try: `if let Some(<item>) = maybe_next_node`
[INFO] [stdout] 159 |                     // handle insert in the middle
[INFO] [stdout] 160 |                     let next_node = maybe_next_node.unwrap();
[INFO] [stdout]     |                                     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:137:9
[INFO] [stdout]     |
[INFO] [stdout] 137 | /         return match maybe_prev_node {
[INFO] [stdout] 138 | |             // insert at head
[INFO] [stdout] 139 | |             None => {
[INFO] [stdout] 140 | |                 let maybe_prev_head_ref: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] ...   |
[INFO] [stdout] 174 | |         };
[INFO] [stdout]     | |_________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 137 ~         match maybe_prev_node {
[INFO] [stdout] 138 +             // insert at head
[INFO] [stdout] 139 +             None => {
[INFO] [stdout] 140 +                 let maybe_prev_head_ref: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] 141 +                     self.head.as_ref().map(Rc::clone);
[INFO] [stdout] 142 +                 if maybe_prev_head_ref.is_some() {
[INFO] [stdout] 143 +                     let prev_head_ref = maybe_prev_head_ref.unwrap();
[INFO] [stdout] 144 +                     let new_head = Rc::new(RefCell::new(Node::new(key, value)));
[INFO] [stdout] 145 +                     new_head.borrow_mut().right = self.head.take();
[INFO] [stdout] 146 +                     self.head = Some(new_head);
[INFO] [stdout] 147 +                     prev_head_ref.borrow_mut().left = self.head.as_ref().map(Rc::downgrade);
[INFO] [stdout] 148 +                 } else {
[INFO] [stdout] 149 +                     self.head = Some(Rc::new(RefCell::new(Node::new(key, value))));
[INFO] [stdout] 150 +                 }
[INFO] [stdout] 151 +                 self.size += 1;
[INFO] [stdout] 152 +                 Rc::clone(self.head.as_ref().unwrap())
[INFO] [stdout] 153 +             }
[INFO] [stdout] 154 +             Some(prev_node) => {
[INFO] [stdout] 155 +                 let maybe_next_node: Option<Rc<RefCell<Node<K, V>>>> =
[INFO] [stdout] 156 +                     prev_node.borrow().right.as_ref().map(Rc::clone);
[INFO] [stdout] 157 +                 let new_node = Rc::new(RefCell::new(Node::new(key, value)));
[INFO] [stdout] 158 +                 if maybe_next_node.is_some() {
[INFO] [stdout] 159 +                     // handle insert in the middle
[INFO] [stdout] 160 +                     let next_node = maybe_next_node.unwrap();
[INFO] [stdout] 161 +                     next_node.borrow_mut().left = Some(Rc::downgrade(&new_node));
[INFO] [stdout] 162 +                     new_node.borrow_mut().right = prev_node.borrow_mut().right.take();
[INFO] [stdout] 163 +                     new_node.borrow_mut().left = Some(Rc::downgrade(&prev_node));
[INFO] [stdout] 164 +                     prev_node.borrow_mut().right = Some(new_node);
[INFO] [stdout] 165 +                     self.size += 1;
[INFO] [stdout] 166 +                 } else {
[INFO] [stdout] 167 +                     // handle insert at tail
[INFO] [stdout] 168 +                     new_node.borrow_mut().left = Some(Rc::downgrade(&prev_node));
[INFO] [stdout] 169 +                     prev_node.borrow_mut().right = Some(new_node);
[INFO] [stdout] 170 +                     self.size += 1;
[INFO] [stdout] 171 +                 }
[INFO] [stdout] 172 +                 Rc::clone(prev_node.borrow().right.as_ref().unwrap())
[INFO] [stdout] 173 +             }
[INFO] [stdout] 174 ~         }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_next_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:190:29
[INFO] [stdout]     |
[INFO] [stdout] 189 |         if maybe_next_node.is_some() {
[INFO] [stdout]     |         ---------------------------- help: try: `if let Some(<item>) = maybe_next_node`
[INFO] [stdout] 190 |             let next_node = maybe_next_node.unwrap();
[INFO] [stdout]     |                             ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:207:29
[INFO] [stdout]     |
[INFO] [stdout] 206 |         if maybe_node.is_some() {
[INFO] [stdout]     |         ----------------------- help: try: `if let Some(<item>) = &maybe_node`
[INFO] [stdout] 207 |             let to_delete = maybe_node.as_ref().unwrap();
[INFO] [stdout]     |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_prev_node` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:210:58
[INFO] [stdout]     |
[INFO] [stdout] 209 |             if maybe_prev_node.is_some() {
[INFO] [stdout]     |             ---------------------------- help: try: `if let Some(<item>) = maybe_prev_node`
[INFO] [stdout] 210 |                 let prev_node: Rc<RefCell<Node<K, V>>> = maybe_prev_node.unwrap();
[INFO] [stdout]     |                                                          ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_new_next` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:214:36
[INFO] [stdout]     |
[INFO] [stdout] 213 |                 if maybe_new_next.is_some() {
[INFO] [stdout]     |                 --------------------------- help: try: `if let Some(<item>) = maybe_new_next`
[INFO] [stdout] 214 |                     let new_next = maybe_new_next.unwrap();
[INFO] [stdout]     |                                    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `maybe_current` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:238:27
[INFO] [stdout]     |
[INFO] [stdout] 237 |         if maybe_current.is_some() {
[INFO] [stdout]     |         -------------------------- help: try: `if let Some(<item>) = maybe_current`
[INFO] [stdout] 238 |             let current = maybe_current.unwrap();
[INFO] [stdout]     |                           ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: you should consider adding a `Default` implementation for `SkipList<K, V>`
[INFO] [stdout]    --> src/skiplist.rs:279:5
[INFO] [stdout]     |
[INFO] [stdout] 279 | /     pub fn new() -> SkipList<K, V> {
[INFO] [stdout] 280 | |         let levels = vec![Level::new()];
[INFO] [stdout] 281 | |         SkipList { size: 0, levels }
[INFO] [stdout] 282 | |     }
[INFO] [stdout]     | |_____^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#new_without_default
[INFO] [stdout]     = note: `#[warn(clippy::new_without_default)]` on by default
[INFO] [stdout] help: try adding this
[INFO] [stdout]     |
[INFO] [stdout] 266 + impl<K, V> Default for SkipList<K, V>
[INFO] [stdout] 267 + where
[INFO] [stdout] 268 +     K: Ord + Clone + Display,
[INFO] [stdout] 269 +     V: Clone,
[INFO] [stdout] 270 +  {
[INFO] [stdout] 271 +     fn default() -> Self {
[INFO] [stdout] 272 +         Self::new()
[INFO] [stdout] 273 +     }
[INFO] [stdout] 274 + }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: doc list item overindented
[INFO] [stdout]    --> src/skiplist.rs:288:9
[INFO] [stdout]     |
[INFO] [stdout] 288 |     ///             This is also used as the sort key.
[INFO] [stdout]     |         ^^^^^^^^^^^^ help: try using `  ` (2 spaces)
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
[INFO] [stdout]     = note: `#[warn(clippy::doc_overindented_list_items)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: length comparison to zero
[INFO] [stdout]    --> src/skiplist.rs:303:12
[INFO] [stdout]     |
[INFO] [stdout] 303 |         if self.levels.len() > 0 {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!self.levels.is_empty()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
[INFO] [stdout]     = note: `#[warn(clippy::len_zero)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
[INFO] [stdout]    --> src/skiplist.rs:307:13
[INFO] [stdout]     |
[INFO] [stdout] 307 | /             match insertion_path.get(0).unwrap() {
[INFO] [stdout] 308 | |                 Insertion::Before => {
[INFO] [stdout] 309 | |                     is_head = true;
[INFO] [stdout] ...   |
[INFO] [stdout] 312 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_match
[INFO] [stdout]     = note: `#[warn(clippy::single_match)]` on by default
[INFO] [stdout] help: try
[INFO] [stdout]     |
[INFO] [stdout] 307 ~             if let Insertion::Before = insertion_path.get(0).unwrap() {
[INFO] [stdout] 308 +                 is_head = true;
[INFO] [stdout] 309 +             }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: accessing first element with `insertion_path.get(0)`
[INFO] [stdout]    --> src/skiplist.rs:307:19
[INFO] [stdout]     |
[INFO] [stdout] 307 |             match insertion_path.get(0).unwrap() {
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^^^ help: try: `insertion_path.first()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#get_first
[INFO] [stdout]     = note: `#[warn(clippy::get_first)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:509:9
[INFO] [stdout]     |
[INFO] [stdout] 509 | /         return match insertion {
[INFO] [stdout] 510 | |             Insertion::Before => {
[INFO] [stdout] 511 | |                 let new_head = self.levels[level].insert(key.clone(), value.clone());
[INFO] [stdout] 512 | |                 Rc::clone(&new_head)
[INFO] [stdout] ...   |
[INFO] [stdout] 519 | |         };
[INFO] [stdout]     | |_________^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 509 ~         match insertion {
[INFO] [stdout] 510 +             Insertion::Before => {
[INFO] [stdout] 511 +                 let new_head = self.levels[level].insert(key.clone(), value.clone());
[INFO] [stdout] 512 +                 Rc::clone(&new_head)
[INFO] [stdout] 513 +             }
[INFO] [stdout] 514 +             Insertion::After(node) => {
[INFO] [stdout] 515 +                 let new_node =
[INFO] [stdout] 516 +                     self.levels[level].insert_after(key.clone(), value.clone(), Rc::clone(node));
[INFO] [stdout] 517 +                 Rc::clone(&new_node)
[INFO] [stdout] 518 +             }
[INFO] [stdout] 519 ~         }
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `head` after checking its variant with `is_some`
[INFO] [stdout]    --> src/skiplist.rs:530:32
[INFO] [stdout]     |
[INFO] [stdout] 529 |             if head.is_some() {
[INFO] [stdout]     |             ----------------- help: try: `if let Some(<item>) = head`
[INFO] [stdout] 530 |                 let head_ref = head.unwrap();
[INFO] [stdout]     |                                ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unneeded `return` statement
[INFO] [stdout]    --> src/skiplist.rs:571:9
[INFO] [stdout]     |
[INFO] [stdout] 571 |         return random > 0.50;
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
[INFO] [stdout] help: remove `return`
[INFO] [stdout]     |
[INFO] [stdout] 571 -         return random > 0.50;
[INFO] [stdout] 571 +         random > 0.50
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.66s
[INFO] running `Command { std: "docker" "inspect" "2371ab5a9c34063c44beed5c76775e239aa6976d0f3b0549a575fcd2adcfe21f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2371ab5a9c34063c44beed5c76775e239aa6976d0f3b0549a575fcd2adcfe21f", kill_on_drop: false }`
[INFO] [stdout] 2371ab5a9c34063c44beed5c76775e239aa6976d0f3b0549a575fcd2adcfe21f