Fix all remaining warnings in helix-core except for two.

I'm not sure how to address them, because they look like they
might be bugs, and code is involved.  Will poke the relevant people.

helix-core/src/auto_pairs.rs

@@ -139,7 +139,7 @@ fn handle_close(doc: &Rope, selection: &Selection, _open: char, close: char) ->
 }
 
 // handle cases where open and close is the same, or in triples ("""docstring""")
-fn handle_same(doc: &Rope, selection: &Selection, token: char) -> Option<Transaction> {
+fn handle_same(_doc: &Rope, _selection: &Selection, _token: char) -> Option<Transaction> {
     // if not cursor but selection, wrap
     // let next = next char
 

helix-core/src/history.rs

@@ -126,7 +126,6 @@ impl History {
         let last_child = current_revision.last_child?;
         self.current = last_child.get();
 
-        let last_child_revision = &self.revisions[last_child.get()];
         Some(&self.revisions[last_child.get()].transaction)
     }
 
@@ -376,21 +375,21 @@ mod test {
             if let Some(transaction) = history.undo() {
                 transaction.apply(&mut state.doc);
             }
-        };
+        }
 
         fn earlier(history: &mut History, state: &mut State, uk: UndoKind) {
             let txns = history.earlier(uk);
             for txn in txns {
                 txn.apply(&mut state.doc);
             }
-        };
+        }
 
         fn later(history: &mut History, state: &mut State, uk: UndoKind) {
             let txns = history.later(uk);
             for txn in txns {
                 txn.apply(&mut state.doc);
             }
-        };
+        }
 
         fn commit_change(
             history: &mut History,
@@ -401,7 +400,7 @@ mod test {
             let txn = Transaction::change(&state.doc, vec![change.clone()].into_iter());
             history.commit_revision_at_timestamp(&txn, &state, instant);
             txn.apply(&mut state.doc);
-        };
+        }
 
         let t0 = Instant::now();
         let t = |n| t0.checked_add(Duration::from_secs(n)).unwrap();

helix-core/src/indent.rs

@@ -7,7 +7,7 @@ use crate::{
 
 /// To determine indentation of a newly inserted line, figure out the indentation at the last col
 /// of the previous line.
-
+#[allow(dead_code)]
 fn indent_level_for_line(line: RopeSlice, tab_width: usize) -> usize {
     let mut len = 0;
     for ch in line.chars() {
@@ -98,12 +98,13 @@ fn calculate_indentation(query: &IndentQuery, node: Option<Node>, newline: bool)
     increment as usize
 }
 
+#[allow(dead_code)]
 fn suggested_indent_for_line(
     language_config: &LanguageConfiguration,
     syntax: Option<&Syntax>,
     text: RopeSlice,
     line_num: usize,
-    tab_width: usize,
+    _tab_width: usize,
 ) -> usize {
     if let Some(start) = find_first_non_whitespace_char(text.line(line_num)) {
         return suggested_indent_for_pos(

helix-core/src/match_brackets.rs

@@ -12,7 +12,7 @@ pub fn find(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<usize> {
     // most naive implementation: find the innermost syntax node, if we're at the edge of a node,
     // return the other edge.
 
-    let mut node = match tree
+    let node = match tree
         .root_node()
         .named_descendant_for_byte_range(byte_pos, byte_pos)
     {

helix-core/src/movement.rs

@@ -113,7 +113,7 @@ pub fn move_prev_long_word_start(slice: RopeSlice, range: Range, count: usize) -
     word_move(slice, range, count, WordMotionTarget::PrevLongWordStart)
 }
 
-fn word_move(slice: RopeSlice, mut range: Range, count: usize, target: WordMotionTarget) -> Range {
+fn word_move(slice: RopeSlice, range: Range, count: usize, target: WordMotionTarget) -> Range {
     (0..count).fold(range, |range, _| {
         slice.chars_at(range.head).range_to_target(target, range)
     })
@@ -179,7 +179,6 @@ enum WordMotionPhase {
 
 impl CharHelpers for Chars<'_> {
     fn range_to_target(&mut self, target: WordMotionTarget, origin: Range) -> Range {
-        let range = origin;
         // Characters are iterated forward or backwards depending on the motion direction.
         let characters: Box<dyn Iterator<Item = char>> = match target {
             WordMotionTarget::PrevWordStart | WordMotionTarget::PrevLongWordStart => {

helix-core/src/position.rs

@@ -80,8 +80,8 @@ mod test {
 
     #[test]
     fn test_coords_at_pos() {
-        let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
-        let slice = text.slice(..);
+        // let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
+        // let slice = text.slice(..);
         // assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
         // assert_eq!(coords_at_pos(slice, 5), (0, 5).into()); // position on \n
         // assert_eq!(coords_at_pos(slice, 6), (1, 0).into()); // position on w

helix-core/src/selection.rs

@@ -345,10 +345,8 @@ pub fn select_on_matches(
         // TODO: can't avoid occasional allocations since Regex can't operate on chunks yet
         let fragment = sel.fragment(text);
 
-        let mut sel_start = sel.from();
-        let sel_end = sel.to();
-
-        let mut start_byte = text.char_to_byte(sel_start);
+        let sel_start = sel.from();
+        let start_byte = text.char_to_byte(sel_start);
 
         for mat in regex.find_iter(&fragment) {
             // TODO: retain range direction
@@ -379,10 +377,10 @@ pub fn split_on_matches(
         // TODO: can't avoid occasional allocations since Regex can't operate on chunks yet
         let fragment = sel.fragment(text);
 
-        let mut sel_start = sel.from();
+        let sel_start = sel.from();
         let sel_end = sel.to();
 
-        let mut start_byte = text.char_to_byte(sel_start);
+        let start_byte = text.char_to_byte(sel_start);
 
         let mut start = sel_start;
 
@@ -411,7 +409,7 @@ mod test {
     #[test]
     #[should_panic]
     fn test_new_empty() {
-        let sel = Selection::new(smallvec![], 0);
+        let _ = Selection::new(smallvec![], 0);
     }
 
     #[test]

helix-core/src/syntax.rs

@@ -166,7 +166,7 @@ impl LanguageConfiguration {
             None
         } else {
             let language = get_language(self.language_id);
-            let mut config = HighlightConfiguration::new(
+            let config = HighlightConfiguration::new(
                 language,
                 &highlights_query,
                 &injections_query,
@@ -332,7 +332,8 @@ impl Syntax {
 
         // update root layer
         PARSER.with(|ts_parser| {
-            syntax.root_layer.parse(
+            // TODO: handle the returned `Result` properly.
+            let _ = syntax.root_layer.parse(
                 &mut ts_parser.borrow_mut(),
                 &syntax.config,
                 source,
@@ -387,7 +388,7 @@ impl Syntax {
         source: RopeSlice<'a>,
         range: Option<std::ops::Range<usize>>,
         cancellation_flag: Option<&'a AtomicUsize>,
-        mut injection_callback: impl FnMut(&str) -> Option<&'a HighlightConfiguration> + 'a,
+        injection_callback: impl FnMut(&str) -> Option<&'a HighlightConfiguration> + 'a,
     ) -> impl Iterator<Item = Result<HighlightEvent, Error>> + 'a {
         // The `captures` iterator borrows the `Tree` and the `QueryCursor`, which
         // prevents them from being moved. But both of these values are really just
@@ -494,8 +495,8 @@ impl LanguageLayer {
         ts_parser: &mut TsParser,
         config: &HighlightConfiguration,
         source: &Rope,
-        mut depth: usize,
-        mut ranges: Vec<Range>,
+        _depth: usize,
+        ranges: Vec<Range>,
     ) -> Result<(), Error> {
         if ts_parser.parser.set_included_ranges(&ranges).is_ok() {
             ts_parser
@@ -1644,13 +1645,13 @@ fn injection_for_match<'a>(
     (language_name, content_node, include_children)
 }
 
-fn shrink_and_clear<T>(vec: &mut Vec<T>, capacity: usize) {
-    if vec.len() > capacity {
-        vec.truncate(capacity);
-        vec.shrink_to_fit();
-    }
-    vec.clear();
-}
+// fn shrink_and_clear<T>(vec: &mut Vec<T>, capacity: usize) {
+//     if vec.len() > capacity {
+//         vec.truncate(capacity);
+//         vec.shrink_to_fit();
+//     }
+//     vec.clear();
+// }
 
 pub struct Merge<I> {
     iter: I,
@@ -1691,7 +1692,7 @@ impl<I: Iterator<Item = HighlightEvent>> Iterator for Merge<I> {
         loop {
             match (self.next_event, &self.next_span) {
                 // this happens when range is partially or fully offscreen
-                (Some(Source { start, end }), Some((span, range))) if start > range.start => {
+                (Some(Source { start, .. }), Some((span, range))) if start > range.start => {
                     if start > range.end {
                         self.next_span = self.spans.next();
                     } else {
@@ -1711,7 +1712,7 @@ impl<I: Iterator<Item = HighlightEvent>> Iterator for Merge<I> {
                 self.next_event = self.iter.next();
                 Some(HighlightEnd)
             }
-            (Some(Source { start, end }), Some((span, range))) if start < range.start => {
+            (Some(Source { start, end }), Some((_, range))) if start < range.start => {
                 let intersect = range.start.min(end);
                 let event = Source {
                     start,
@@ -1766,7 +1767,7 @@ impl<I: Iterator<Item = HighlightEvent>> Iterator for Merge<I> {
                 Some(event)
             }
             // can happen if deleting and cursor at EOF, and diagnostic reaches past the end
-            (None, Some((span, range))) => {
+            (None, Some((_, _))) => {
                 self.next_span = None;
                 None
             }
@@ -1809,7 +1810,7 @@ mod test {
         .collect();
 
         let language = get_language(Lang::Rust);
-        let mut config = HighlightConfiguration::new(
+        let config = HighlightConfiguration::new(
             language,
             &std::fs::read_to_string(
                 "../helix-syntax/languages/tree-sitter-rust/queries/highlights.scm",
@@ -1853,7 +1854,7 @@ mod test {
         use crate::State;
         use tree_sitter::InputEdit;
 
-        let mut state = State::new("hello world!\ntest 123".into());
+        let state = State::new("hello world!\ntest 123".into());
         let transaction = Transaction::change(
             &state.doc,
             vec![(6, 11, Some("test".into())), (12, 17, None)].into_iter(),

helix-core/src/transaction.rs

@@ -163,7 +163,7 @@ impl ChangeSet {
                     head_a = a;
                     head_b = changes_b.next();
                 }
-                (None, val) | (val, None) => return unreachable!("({:?})", val),
+                (None, val) | (val, None) => unreachable!("({:?})", val),
                 (Some(Retain(i)), Some(Retain(j))) => match i.cmp(&j) {
                     Ordering::Less => {
                         changes.retain(i);
@@ -202,7 +202,7 @@ impl ChangeSet {
                         }
                     }
                 }
-                (Some(Insert(mut s)), Some(Retain(j))) => {
+                (Some(Insert(s)), Some(Retain(j))) => {
                     let len = s.chars().count();
                     match len.cmp(&j) {
                         Ordering::Less => {
@@ -274,7 +274,6 @@ impl ChangeSet {
         let mut changes = Self::with_capacity(self.changes.len());
 
         let mut pos = 0;
-        let mut len = 0;
 
         for change in &self.changes {
             use Operation::*;
@@ -700,7 +699,7 @@ mod test {
 
     #[test]
     fn changes_iter() {
-        let mut state = State::new("hello world!\ntest 123".into());
+        let state = State::new("hello world!\ntest 123".into());
         let changes = vec![(6, 11, Some("void".into())), (12, 17, None)];
         let transaction = Transaction::change(&state.doc, changes.clone().into_iter());
         assert_eq!(transaction.changes_iter().collect::<Vec<_>>(), changes);
@@ -732,7 +731,7 @@ mod test {
         // retain 1, e
         // retain 2, l
 
-        let mut changes = t1
+        let changes = t1
             .changes
             .compose(t2.changes)
             .compose(t3.changes)
@@ -747,7 +746,7 @@ mod test {
     #[test]
     fn combine_with_empty() {
         let empty = Rope::from("");
-        let mut a = ChangeSet::new(&empty);
+        let a = ChangeSet::new(&empty);
 
         let mut b = ChangeSet::new(&empty);
         b.insert("a".into());
@@ -763,7 +762,7 @@ mod test {
         const TEST_CASE: &'static str = "Hello, これはヘリックスエディターです！";
 
         let empty = Rope::from("");
-        let mut a = ChangeSet::new(&empty);
+        let a = ChangeSet::new(&empty);
 
         let mut b = ChangeSet::new(&empty);
         b.insert(TEST_CASE.into());