[INFO] fetching crate tree-rizzen-yazston 0.4.0...
[INFO] linting tree-rizzen-yazston-0.4.0 against nightly for clippy-nonminimal_bool-denied
[INFO] extracting crate tree-rizzen-yazston 0.4.0 into /workspace/builds/worker-7-tc1/source
[INFO] started tweaking crates.io crate tree-rizzen-yazston 0.4.0
[INFO] finished tweaking crates.io crate tree-rizzen-yazston 0.4.0
[INFO] tweaked toml for crates.io crate tree-rizzen-yazston 0.4.0 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate tree-rizzen-yazston 0.4.0 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] 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] 17082c886f35cbd069f5200767f5f0738d7cd3e690934fdb77fcbfba94a0f271
[INFO] running `Command { std: "docker" "start" "-a" "17082c886f35cbd069f5200767f5f0738d7cd3e690934fdb77fcbfba94a0f271", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "17082c886f35cbd069f5200767f5f0738d7cd3e690934fdb77fcbfba94a0f271", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "17082c886f35cbd069f5200767f5f0738d7cd3e690934fdb77fcbfba94a0f271", kill_on_drop: false }`
[INFO] [stdout] 17082c886f35cbd069f5200767f5f0738d7cd3e690934fdb77fcbfba94a0f271
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] 3fa739e1e8ca9b290bf951ccf6fa5d9bf5fa099694380d925bbf9546e9e24b99
[INFO] running `Command { std: "docker" "start" "-a" "3fa739e1e8ca9b290bf951ccf6fa5d9bf5fa099694380d925bbf9546e9e24b99", kill_on_drop: false }`
[INFO] [stderr]     Checking tree-rizzen-yazston v0.4.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: you should consider adding a `Default` implementation for `Tree`
[INFO] [stdout]   --> src/tree.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 44 | /     pub fn new() -> Self {
[INFO] [stdout] 45 | |         Tree {
[INFO] [stdout] 46 | |             nodes: Vec::new(),
[INFO] [stdout] 47 | |             root: None
[INFO] [stdout] 48 | |         }
[INFO] [stdout] 49 | |     }
[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] 29 + impl Default for Tree {
[INFO] [stdout] 30 +     fn default() -> Self {
[INFO] [stdout] 31 +         Self::new()
[INFO] [stdout] 32 +     }
[INFO] [stdout] 33 + }
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:101:12
[INFO] [stdout]     |
[INFO] [stdout] 101 |         if !self.root.is_none() {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^ help: try: `self.root.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout]     = note: `#[warn(clippy::nonminimal_bool)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:177:12
[INFO] [stdout]     |
[INFO] [stdout] 177 |         if !self.root.is_none() {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^ help: try: `self.root.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:264:16
[INFO] [stdout]     |
[INFO] [stdout] 264 |             if !_parent.is_none() {
[INFO] [stdout]     |                ^^^^^^^^^^^^^^^^^^ help: try: `_parent.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `_parent` after checking its variant with `is_none`
[INFO] [stdout]    --> src/tree.rs:265:30
[INFO] [stdout]     |
[INFO] [stdout] 264 |             if !_parent.is_none() {
[INFO] [stdout]     |                 ----------------- the check is happening here
[INFO] [stdout] 265 |                 let parent = _parent.unwrap();
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: try using `match`
[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: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:316:16
[INFO] [stdout]     |
[INFO] [stdout] 316 |             if !_parent.is_none() {
[INFO] [stdout]     |                ^^^^^^^^^^^^^^^^^^ help: try: `_parent.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `_parent` after checking its variant with `is_none`
[INFO] [stdout]    --> src/tree.rs:317:30
[INFO] [stdout]     |
[INFO] [stdout] 316 |             if !_parent.is_none() {
[INFO] [stdout]     |                 ----------------- the check is happening here
[INFO] [stdout] 317 |                 let parent = _parent.unwrap();
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: try using `match`
[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 seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
[INFO] [stdout]    --> src/tree.rs:402:9
[INFO] [stdout]     |
[INFO] [stdout] 402 | /         match self.is_ancestor_of( destination, source ) {
[INFO] [stdout] 403 | |             Ok( _ ) => return Err( TreeError::IsAncestorOf( source, destination ) ),
[INFO] [stdout] 404 | |             Err( _ ) => {}
[INFO] [stdout] 405 | |         };
[INFO] [stdout]     | |_________^ help: try: `if let Ok( _ ) = self.is_ancestor_of( destination, source ) { return Err( TreeError::IsAncestorOf( source, destination ) ) }`
[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] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:490:13
[INFO] [stdout]     |
[INFO] [stdout] 490 | /             if let Some( _ ) = option {
[INFO] [stdout] 491 | |                 return true;
[INFO] [stdout] 492 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:489:22
[INFO] [stdout]     |
[INFO] [stdout] 489 |         if let Some( option ) = self.nodes.get( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 490 |             if let Some( _ ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[INFO] [stdout]     = note: `#[warn(clippy::collapsible_match)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: redundant pattern matching, consider using `is_some()`
[INFO] [stdout]    --> src/tree.rs:490:20
[INFO] [stdout]     |
[INFO] [stdout] 490 |             if let Some( _ ) = option {
[INFO] [stdout]     |             -------^^^^^^^^^--------- help: try: `if option.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_pattern_matching
[INFO] [stdout]     = note: `#[warn(clippy::redundant_pattern_matching)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enclosing `Ok` and `?` operator are unneeded
[INFO] [stdout]    --> src/tree.rs:592:9
[INFO] [stdout]     |
[INFO] [stdout] 592 |         Ok( self.is_ancestor_of( parent, is_ancestor )? )
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_question_mark
[INFO] [stdout]     = note: `#[warn(clippy::needless_question_mark)]` on by default
[INFO] [stdout] help: remove the enclosing `Ok` and `?` operator
[INFO] [stdout]     |
[INFO] [stdout] 592 -         Ok( self.is_ancestor_of( parent, is_ancestor )? )
[INFO] [stdout] 592 +         self.is_ancestor_of( parent, is_ancestor )
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this expression creates a reference which is immediately dereferenced by the compiler
[INFO] [stdout]    --> src/tree.rs:615:13
[INFO] [stdout]     |
[INFO] [stdout] 615 |         Ok( &index_node.children.as_ref().unwrap() )
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `index_node.children.as_ref().unwrap()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
[INFO] [stdout]     = note: `#[warn(clippy::needless_borrow)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Tree` has a public `len` method, but no `is_empty` method
[INFO] [stdout]    --> src/tree.rs:733:5
[INFO] [stdout]     |
[INFO] [stdout] 733 |     pub fn len( &self ) -> usize {
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty
[INFO] [stdout]     = note: `#[warn(clippy::len_without_is_empty)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this expression creates a reference which is immediately dereferenced by the compiler
[INFO] [stdout]    --> src/tree.rs:808:13
[INFO] [stdout]     |
[INFO] [stdout] 808 |         Ok( &index_node.data.as_ref().unwrap() )
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `index_node.data.as_ref().unwrap()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:835:13
[INFO] [stdout]     |
[INFO] [stdout] 835 | /             if let Some( node ) = option {
[INFO] [stdout] 836 | |                 return Some( node );
[INFO] [stdout] 837 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:834:22
[INFO] [stdout]     |
[INFO] [stdout] 834 |         if let Some( option ) = self.nodes.get( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 835 |             if let Some( node ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:844:13
[INFO] [stdout]     |
[INFO] [stdout] 844 | /             if let Some( node ) = option {
[INFO] [stdout] 845 | |                 return Some( node );
[INFO] [stdout] 846 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:843:22
[INFO] [stdout]     |
[INFO] [stdout] 843 |         if let Some( option ) = self.nodes.get_mut( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 844 |             if let Some( node ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: you should consider adding a `Default` implementation for `Tree`
[INFO] [stdout]   --> src/tree.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 44 | /     pub fn new() -> Self {
[INFO] [stdout] 45 | |         Tree {
[INFO] [stdout] 46 | |             nodes: Vec::new(),
[INFO] [stdout] 47 | |             root: None
[INFO] [stdout] 48 | |         }
[INFO] [stdout] 49 | |     }
[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] 29 + impl Default for Tree {
[INFO] [stdout] 30 +     fn default() -> Self {
[INFO] [stdout] 31 +         Self::new()
[INFO] [stdout] 32 +     }
[INFO] [stdout] 33 + }
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:101:12
[INFO] [stdout]     |
[INFO] [stdout] 101 |         if !self.root.is_none() {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^ help: try: `self.root.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout]     = note: `#[warn(clippy::nonminimal_bool)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:177:12
[INFO] [stdout]     |
[INFO] [stdout] 177 |         if !self.root.is_none() {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^^^^^^^ help: try: `self.root.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:264:16
[INFO] [stdout]     |
[INFO] [stdout] 264 |             if !_parent.is_none() {
[INFO] [stdout]     |                ^^^^^^^^^^^^^^^^^^ help: try: `_parent.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `_parent` after checking its variant with `is_none`
[INFO] [stdout]    --> src/tree.rs:265:30
[INFO] [stdout]     |
[INFO] [stdout] 264 |             if !_parent.is_none() {
[INFO] [stdout]     |                 ----------------- the check is happening here
[INFO] [stdout] 265 |                 let parent = _parent.unwrap();
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: try using `match`
[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: this boolean expression can be simplified
[INFO] [stdout]    --> src/tree.rs:316:16
[INFO] [stdout]     |
[INFO] [stdout] 316 |             if !_parent.is_none() {
[INFO] [stdout]     |                ^^^^^^^^^^^^^^^^^^ help: try: `_parent.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: called `unwrap` on `_parent` after checking its variant with `is_none`
[INFO] [stdout]    --> src/tree.rs:317:30
[INFO] [stdout]     |
[INFO] [stdout] 316 |             if !_parent.is_none() {
[INFO] [stdout]     |                 ----------------- the check is happening here
[INFO] [stdout] 317 |                 let parent = _parent.unwrap();
[INFO] [stdout]     |                              ^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: try using `match`
[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 seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
[INFO] [stdout]    --> src/tree.rs:402:9
[INFO] [stdout]     |
[INFO] [stdout] 402 | /         match self.is_ancestor_of( destination, source ) {
[INFO] [stdout] 403 | |             Ok( _ ) => return Err( TreeError::IsAncestorOf( source, destination ) ),
[INFO] [stdout] 404 | |             Err( _ ) => {}
[INFO] [stdout] 405 | |         };
[INFO] [stdout]     | |_________^ help: try: `if let Ok( _ ) = self.is_ancestor_of( destination, source ) { return Err( TreeError::IsAncestorOf( source, destination ) ) }`
[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] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:490:13
[INFO] [stdout]     |
[INFO] [stdout] 490 | /             if let Some( _ ) = option {
[INFO] [stdout] 491 | |                 return true;
[INFO] [stdout] 492 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:489:22
[INFO] [stdout]     |
[INFO] [stdout] 489 |         if let Some( option ) = self.nodes.get( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 490 |             if let Some( _ ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[INFO] [stdout]     = note: `#[warn(clippy::collapsible_match)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: redundant pattern matching, consider using `is_some()`
[INFO] [stdout]    --> src/tree.rs:490:20
[INFO] [stdout]     |
[INFO] [stdout] 490 |             if let Some( _ ) = option {
[INFO] [stdout]     |             -------^^^^^^^^^--------- help: try: `if option.is_some()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_pattern_matching
[INFO] [stdout]     = note: `#[warn(clippy::redundant_pattern_matching)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enclosing `Ok` and `?` operator are unneeded
[INFO] [stdout]    --> src/tree.rs:592:9
[INFO] [stdout]     |
[INFO] [stdout] 592 |         Ok( self.is_ancestor_of( parent, is_ancestor )? )
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_question_mark
[INFO] [stdout]     = note: `#[warn(clippy::needless_question_mark)]` on by default
[INFO] [stdout] help: remove the enclosing `Ok` and `?` operator
[INFO] [stdout]     |
[INFO] [stdout] 592 -         Ok( self.is_ancestor_of( parent, is_ancestor )? )
[INFO] [stdout] 592 +         self.is_ancestor_of( parent, is_ancestor )
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this expression creates a reference which is immediately dereferenced by the compiler
[INFO] [stdout]    --> src/tree.rs:615:13
[INFO] [stdout]     |
[INFO] [stdout] 615 |         Ok( &index_node.children.as_ref().unwrap() )
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `index_node.children.as_ref().unwrap()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
[INFO] [stdout]     = note: `#[warn(clippy::needless_borrow)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Tree` has a public `len` method, but no `is_empty` method
[INFO] [stdout]    --> src/tree.rs:733:5
[INFO] [stdout]     |
[INFO] [stdout] 733 |     pub fn len( &self ) -> usize {
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_without_is_empty
[INFO] [stdout]     = note: `#[warn(clippy::len_without_is_empty)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this expression creates a reference which is immediately dereferenced by the compiler
[INFO] [stdout]    --> src/tree.rs:808:13
[INFO] [stdout]     |
[INFO] [stdout] 808 |         Ok( &index_node.data.as_ref().unwrap() )
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `index_node.data.as_ref().unwrap()`
[INFO] [stdout]     |
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:835:13
[INFO] [stdout]     |
[INFO] [stdout] 835 | /             if let Some( node ) = option {
[INFO] [stdout] 836 | |                 return Some( node );
[INFO] [stdout] 837 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:834:22
[INFO] [stdout]     |
[INFO] [stdout] 834 |         if let Some( option ) = self.nodes.get( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 835 |             if let Some( node ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: this `if let` can be collapsed into the outer `if let`
[INFO] [stdout]    --> src/tree.rs:844:13
[INFO] [stdout]     |
[INFO] [stdout] 844 | /             if let Some( node ) = option {
[INFO] [stdout] 845 | |                 return Some( node );
[INFO] [stdout] 846 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout]     |
[INFO] [stdout] help: the outer pattern can be modified to include the inner pattern
[INFO] [stdout]    --> src/tree.rs:843:22
[INFO] [stdout]     |
[INFO] [stdout] 843 |         if let Some( option ) = self.nodes.get_mut( node_index ) {
[INFO] [stdout]     |                      ^^^^^^ replace this binding
[INFO] [stdout] 844 |             if let Some( node ) = option {
[INFO] [stdout]     |                    ^^^^^^^^^^^^ with this pattern
[INFO] [stdout]     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
[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]    --> tests/tree.rs:171:5
[INFO] [stdout]     |
[INFO] [stdout] 171 | /     match tree.parent( 0 ).err().unwrap() {
[INFO] [stdout] 172 | |         TreeError::RootHasNoParent( _ ) => result = true,
[INFO] [stdout] 173 | |         _ => {}
[INFO] [stdout] 174 | |     };
[INFO] [stdout]     | |_____^ help: try: `if let TreeError::RootHasNoParent( _ ) = tree.parent( 0 ).err().unwrap() { result = true }`
[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] 
[INFO] [stdout] 
[INFO] [stdout] warning: accessing first element with `data_vec_ref.get(0)`
[INFO] [stdout]    --> tests/tree.rs:307:16
[INFO] [stdout]     |
[INFO] [stdout] 307 |     let data = data_vec_ref.get( 0 ).unwrap().downcast_ref::<String>().unwrap();
[INFO] [stdout]     |                ^^^^^^^^^^^^^^^^^^^^^ help: try: `data_vec_ref.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] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.74s
[INFO] running `Command { std: "docker" "inspect" "3fa739e1e8ca9b290bf951ccf6fa5d9bf5fa099694380d925bbf9546e9e24b99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3fa739e1e8ca9b290bf951ccf6fa5d9bf5fa099694380d925bbf9546e9e24b99", kill_on_drop: false }`
[INFO] [stdout] 3fa739e1e8ca9b290bf951ccf6fa5d9bf5fa099694380d925bbf9546e9e24b99