# HG changeset patch
# User Raphaël Gomès <rgomes@octobus.net>
# Date 2020-06-15 16:26:40
# Node ID 26114bd6ec60cb48b5dc52946c2f51a5fb698c7a
# Parent  ef8dcee272acbe22af5829e31c55b694f345ceba

rust: do a clippy pass

This is the result of running `cargo clippy` on hg-core/hg-cpython and fixing
the lints that do not require too much code churn (and would warrant a separate
commit/complete refactor) and only come from our code (a lot of warnings in
hg-cpython come from `rust-cpython`).

Most of those were good lints, two of them was the linter not being smart
enough (or compiler to get up to `clippy`'s level depending on how you see it).

Maybe in the future we could have `clippy` be part of the CI.

Differential Revision: https://phab.mercurial-scm.org/D8635

diff --git a/rust/hg-core/src/ancestors.rs b/rust/hg-core/src/ancestors.rs
--- a/rust/hg-core/src/ancestors.rs
+++ b/rust/hg-core/src/ancestors.rs
@@ -55,19 +55,19 @@ impl<G: Graph> AncestorsIterator<G> {
         let filtered_initrevs = initrevs.into_iter().filter(|&r| r >= stoprev);
         if inclusive {
             let visit: BinaryHeap<Revision> = filtered_initrevs.collect();
-            let seen = visit.iter().map(|&x| x).collect();
+            let seen = visit.iter().cloned().collect();
             return Ok(AncestorsIterator {
-                visit: visit,
-                seen: seen,
-                stoprev: stoprev,
-                graph: graph,
+                visit,
+                seen,
+                stoprev,
+                graph,
             });
         }
         let mut this = AncestorsIterator {
             visit: BinaryHeap::new(),
             seen: HashSet::new(),
-            stoprev: stoprev,
-            graph: graph,
+            stoprev,
+            graph,
         };
         this.seen.insert(NULL_REVISION);
         for rev in filtered_initrevs {
@@ -107,7 +107,7 @@ impl<G: Graph> AncestorsIterator<G> {
     }
 
     pub fn peek(&self) -> Option<Revision> {
-        self.visit.peek().map(|&r| r)
+        self.visit.peek().cloned()
     }
 
     /// Tell if the iterator is about an empty set
@@ -182,8 +182,8 @@ impl<G: Graph + Clone> LazyAncestors<G> 
                 inclusive,
             )?,
             initrevs: v,
-            stoprev: stoprev,
-            inclusive: inclusive,
+            stoprev,
+            inclusive,
         })
     }
 
@@ -211,7 +211,7 @@ impl<G: Graph + Clone> LazyAncestors<G> 
 impl<G: Graph> MissingAncestors<G> {
     pub fn new(graph: G, bases: impl IntoIterator<Item = Revision>) -> Self {
         let mut created = MissingAncestors {
-            graph: graph,
+            graph,
             bases: HashSet::new(),
             max_base: NULL_REVISION,
         };
diff --git a/rust/hg-core/src/dagops.rs b/rust/hg-core/src/dagops.rs
--- a/rust/hg-core/src/dagops.rs
+++ b/rust/hg-core/src/dagops.rs
@@ -16,10 +16,10 @@ use super::{Graph, GraphError, Revision,
 use crate::ancestors::AncestorsIterator;
 use std::collections::{BTreeSet, HashSet};
 
-fn remove_parents(
+fn remove_parents<S: std::hash::BuildHasher>(
     graph: &impl Graph,
     rev: Revision,
-    set: &mut HashSet<Revision>,
+    set: &mut HashSet<Revision, S>,
 ) -> Result<(), GraphError> {
     for parent in graph.parents(rev)?.iter() {
         if *parent != NULL_REVISION {
@@ -65,9 +65,9 @@ pub fn heads<'a>(
 ///
 /// # Performance notes
 /// Internally, this function will store a full copy of `revs` in a `Vec`.
-pub fn retain_heads(
+pub fn retain_heads<S: std::hash::BuildHasher>(
     graph: &impl Graph,
-    revs: &mut HashSet<Revision>,
+    revs: &mut HashSet<Revision, S>,
 ) -> Result<(), GraphError> {
     revs.remove(&NULL_REVISION);
     // we need to construct an iterable copy of revs to avoid itering while
@@ -84,9 +84,9 @@ pub fn retain_heads(
 /// Roots of `revs`, passed as a `HashSet`
 ///
 /// They are returned in arbitrary order
-pub fn roots<G: Graph>(
+pub fn roots<G: Graph, S: std::hash::BuildHasher>(
     graph: &G,
-    revs: &HashSet<Revision>,
+    revs: &HashSet<Revision, S>,
 ) -> Result<Vec<Revision>, GraphError> {
     let mut roots: Vec<Revision> = Vec::new();
     for rev in revs {
@@ -229,7 +229,8 @@ mod tests {
         graph: &impl Graph,
         revs: &[Revision],
     ) -> Result<Vec<Revision>, GraphError> {
-        let mut as_vec = roots(graph, &revs.iter().cloned().collect())?;
+        let set: HashSet<_> = revs.iter().cloned().collect();
+        let mut as_vec = roots(graph, &set)?;
         as_vec.sort();
         Ok(as_vec)
     }
diff --git a/rust/hg-core/src/dirstate/dirs_multiset.rs b/rust/hg-core/src/dirstate/dirs_multiset.rs
--- a/rust/hg-core/src/dirstate/dirs_multiset.rs
+++ b/rust/hg-core/src/dirstate/dirs_multiset.rs
@@ -108,7 +108,7 @@ impl DirsMultiset {
         for subpath in files::find_dirs(path.as_ref()) {
             match self.inner.entry(subpath.to_owned()) {
                 Entry::Occupied(mut entry) => {
-                    let val = entry.get().clone();
+                    let val = *entry.get();
                     if val > 1 {
                         entry.insert(val - 1);
                         break;
@@ -137,6 +137,10 @@ impl DirsMultiset {
     pub fn len(&self) -> usize {
         self.inner.len()
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
 }
 
 /// This is basically a reimplementation of `DirsMultiset` that stores the
@@ -156,7 +160,7 @@ impl<'a> DirsChildrenMultiset<'a> {
         let mut new = Self {
             inner: HashMap::default(),
             only_include: only_include
-                .map(|s| s.iter().map(|p| p.as_ref()).collect()),
+                .map(|s| s.iter().map(AsRef::as_ref).collect()),
         };
 
         for path in paths {
diff --git a/rust/hg-core/src/dirstate/dirstate_map.rs b/rust/hg-core/src/dirstate/dirstate_map.rs
--- a/rust/hg-core/src/dirstate/dirstate_map.rs
+++ b/rust/hg-core/src/dirstate/dirstate_map.rs
@@ -223,7 +223,7 @@ impl DirstateMap {
         self.get_non_normal_other_parent_entries()
             .0
             .union(&other)
-            .map(|e| e.to_owned())
+            .map(ToOwned::to_owned)
             .collect()
     }
 
diff --git a/rust/hg-core/src/dirstate/parsers.rs b/rust/hg-core/src/dirstate/parsers.rs
--- a/rust/hg-core/src/dirstate/parsers.rs
+++ b/rust/hg-core/src/dirstate/parsers.rs
@@ -135,7 +135,7 @@ pub fn pack_dirstate(
         }
         let mut new_filename = new_filename.into_vec();
         if let Some(copy) = copy_map.get(filename) {
-            new_filename.push('\0' as u8);
+            new_filename.push(b'\0');
             new_filename.extend(copy.bytes());
         }
 
diff --git a/rust/hg-core/src/dirstate/status.rs b/rust/hg-core/src/dirstate/status.rs
--- a/rust/hg-core/src/dirstate/status.rs
+++ b/rust/hg-core/src/dirstate/status.rs
@@ -127,7 +127,7 @@ fn list_directory(
         if skip_dot_hg && filename.as_bytes() == b".hg" && file_type.is_dir() {
             return Ok(vec![]);
         } else {
-            results.push((HgPathBuf::from(filename), entry))
+            results.push((filename, entry))
         }
     }
 
@@ -164,14 +164,15 @@ fn dispatch_found(
                 (mode ^ st_mode as i32) & 0o100 != 0o000 && options.check_exec;
             let metadata_changed = size >= 0 && (size_changed || mode_changed);
             let other_parent = size == SIZE_FROM_OTHER_PARENT;
+
             if metadata_changed
                 || other_parent
                 || copy_map.contains_key(filename.as_ref())
             {
                 Dispatch::Modified
-            } else if mod_compare(mtime, st_mtime as i32) {
-                Dispatch::Unsure
-            } else if st_mtime == options.last_normal_time {
+            } else if mod_compare(mtime, st_mtime as i32)
+                || st_mtime == options.last_normal_time
+            {
                 // the file may have just been marked as normal and
                 // it may have changed in the same second without
                 // changing its size. This can happen if we quickly
@@ -226,9 +227,9 @@ fn walk_explicit<'a>(
     files
         .unwrap_or(&DEFAULT_WORK)
         .par_iter()
-        .map(move |filename| {
+        .map(move |&filename| {
             // TODO normalization
-            let normalized = filename.as_ref();
+            let normalized = filename;
 
             let buf = match hg_path_to_path_buf(normalized) {
                 Ok(x) => x,
@@ -254,33 +255,31 @@ fn walk_explicit<'a>(
                             )));
                         }
                         Some(Ok((normalized, Dispatch::Unknown)))
+                    } else if file_type.is_dir() {
+                        if options.collect_traversed_dirs {
+                            traversed_sender
+                                .send(normalized.to_owned())
+                                .expect("receiver should outlive sender");
+                        }
+                        Some(Ok((
+                            normalized,
+                            Dispatch::Directory {
+                                was_file: in_dmap.is_some(),
+                            },
+                        )))
                     } else {
-                        if file_type.is_dir() {
-                            if options.collect_traversed_dirs {
-                                traversed_sender
-                                    .send(normalized.to_owned())
-                                    .expect("receiver should outlive sender");
-                            }
-                            Some(Ok((
-                                normalized,
-                                Dispatch::Directory {
-                                    was_file: in_dmap.is_some(),
-                                },
-                            )))
-                        } else {
-                            Some(Ok((
-                                normalized,
-                                Dispatch::Bad(BadMatch::BadType(
-                                    // TODO do more than unknown
-                                    // Support for all `BadType` variant
-                                    // varies greatly between platforms.
-                                    // So far, no tests check the type and
-                                    // this should be good enough for most
-                                    // users.
-                                    BadType::Unknown,
-                                )),
-                            )))
-                        }
+                        Some(Ok((
+                            normalized,
+                            Dispatch::Bad(BadMatch::BadType(
+                                // TODO do more than unknown
+                                // Support for all `BadType` variant
+                                // varies greatly between platforms.
+                                // So far, no tests check the type and
+                                // this should be good enough for most
+                                // users.
+                                BadType::Unknown,
+                            )),
+                        )))
                     };
                 }
                 Err(_) => {
@@ -381,12 +380,10 @@ fn handle_traversed_entry<'a>(
                         .send(Ok((filename.to_owned(), Dispatch::Ignored)))
                         .unwrap();
                 }
-            } else {
-                if options.list_unknown {
-                    files_sender
-                        .send(Ok((filename.to_owned(), Dispatch::Unknown)))
-                        .unwrap();
-                }
+            } else if options.list_unknown {
+                files_sender
+                    .send(Ok((filename.to_owned(), Dispatch::Unknown)))
+                    .unwrap();
             }
         } else if ignore_fn(&filename) && options.list_ignored {
             files_sender
diff --git a/rust/hg-core/src/discovery.rs b/rust/hg-core/src/discovery.rs
--- a/rust/hg-core/src/discovery.rs
+++ b/rust/hg-core/src/discovery.rs
@@ -181,8 +181,8 @@ impl<G: Graph + Clone> PartialDiscovery<
             common: MissingAncestors::new(graph, vec![]),
             missing: HashSet::new(),
             rng: Rng::from_seed(seed),
-            respect_size: respect_size,
-            randomize: randomize,
+            respect_size,
+            randomize,
         }
     }
 
@@ -284,7 +284,7 @@ impl<G: Graph + Clone> PartialDiscovery<
 
     /// Did we acquire full knowledge of our Revisions that the peer has?
     pub fn is_complete(&self) -> bool {
-        self.undecided.as_ref().map_or(false, |s| s.is_empty())
+        self.undecided.as_ref().map_or(false, HashSet::is_empty)
     }
 
     /// Return the heads of the currently known common set of revisions.
@@ -332,7 +332,7 @@ impl<G: Graph + Clone> PartialDiscovery<
             FastHashMap::default();
         for &rev in self.undecided.as_ref().unwrap() {
             for p in ParentsIterator::graph_parents(&self.graph, rev)? {
-                children.entry(p).or_insert_with(|| Vec::new()).push(rev);
+                children.entry(p).or_insert_with(Vec::new).push(rev);
             }
         }
         self.children_cache = Some(children);
@@ -342,7 +342,7 @@ impl<G: Graph + Clone> PartialDiscovery<
     /// Provide statistics about the current state of the discovery process
     pub fn stats(&self) -> DiscoveryStats {
         DiscoveryStats {
-            undecided: self.undecided.as_ref().map(|s| s.len()),
+            undecided: self.undecided.as_ref().map(HashSet::len),
         }
     }
 
diff --git a/rust/hg-core/src/filepatterns.rs b/rust/hg-core/src/filepatterns.rs
--- a/rust/hg-core/src/filepatterns.rs
+++ b/rust/hg-core/src/filepatterns.rs
@@ -324,6 +324,8 @@ pub fn parse_pattern_file_contents<P: As
     warn: bool,
 ) -> Result<(Vec<IgnorePattern>, Vec<PatternFileWarning>), PatternError> {
     let comment_regex = Regex::new(r"((?:^|[^\\])(?:\\\\)*)#.*").unwrap();
+
+    #[allow(clippy::trivial_regex)]
     let comment_escape_regex = Regex::new(r"\\#").unwrap();
     let mut inputs: Vec<IgnorePattern> = vec![];
     let mut warnings: Vec<PatternFileWarning> = vec![];
@@ -458,9 +460,7 @@ pub fn get_patterns_from_file(
         .into_iter()
         .flat_map(|entry| -> PatternResult<_> {
             let IgnorePattern {
-                syntax,
-                pattern,
-                source: _,
+                syntax, pattern, ..
             } = &entry;
             Ok(match syntax {
                 PatternSyntax::Include => {
@@ -504,10 +504,11 @@ impl SubInclude {
             normalize_path_bytes(&get_bytes_from_path(source));
 
         let source_root = get_path_from_bytes(&normalized_source);
-        let source_root = source_root.parent().unwrap_or(source_root.deref());
+        let source_root =
+            source_root.parent().unwrap_or_else(|| source_root.deref());
 
         let path = source_root.join(get_path_from_bytes(pattern));
-        let new_root = path.parent().unwrap_or(path.deref());
+        let new_root = path.parent().unwrap_or_else(|| path.deref());
 
         let prefix = canonical_path(&root_dir, &root_dir, new_root)?;
 
diff --git a/rust/hg-core/src/matchers.rs b/rust/hg-core/src/matchers.rs
--- a/rust/hg-core/src/matchers.rs
+++ b/rust/hg-core/src/matchers.rs
@@ -164,7 +164,7 @@ impl<'a> FileMatcher<'a> {
         files: &'a [impl AsRef<HgPath>],
     ) -> Result<Self, DirstateMapError> {
         Ok(Self {
-            files: HashSet::from_iter(files.iter().map(|f| f.as_ref())),
+            files: HashSet::from_iter(files.iter().map(AsRef::as_ref)),
             dirs: DirsMultiset::from_manifest(files)?,
         })
     }
@@ -190,10 +190,10 @@ impl<'a> Matcher for FileMatcher<'a> {
         if self.files.is_empty() || !self.dirs.contains(&directory) {
             return VisitChildrenSet::Empty;
         }
-        let dirs_as_set = self.dirs.iter().map(|k| k.deref()).collect();
+        let dirs_as_set = self.dirs.iter().map(Deref::deref).collect();
 
         let mut candidates: HashSet<&HgPath> =
-            self.files.union(&dirs_as_set).map(|k| *k).collect();
+            self.files.union(&dirs_as_set).cloned().collect();
         candidates.remove(HgPath::new(b""));
 
         if !directory.as_ref().is_empty() {
@@ -470,7 +470,7 @@ fn roots_dirs_and_parents(
                 _ => unreachable!(),
             })?
             .iter()
-            .map(|k| k.to_owned()),
+            .map(ToOwned::to_owned),
     );
     parents.extend(
         DirsMultiset::from_manifest(&roots)
@@ -479,7 +479,7 @@ fn roots_dirs_and_parents(
                 _ => unreachable!(),
             })?
             .iter()
-            .map(|k| k.to_owned()),
+            .map(ToOwned::to_owned),
     );
 
     Ok(RootsDirsAndParents {
@@ -523,7 +523,7 @@ fn build_match<'a, 'b>(
         let match_subinclude = move |filename: &HgPath| {
             for prefix in prefixes.iter() {
                 if let Some(rel) = filename.relative_to(prefix) {
-                    if (submatchers.get(prefix).unwrap())(rel) {
+                    if (submatchers[prefix])(rel) {
                         return true;
                     }
                 }
diff --git a/rust/hg-core/src/revlog.rs b/rust/hg-core/src/revlog.rs
--- a/rust/hg-core/src/revlog.rs
+++ b/rust/hg-core/src/revlog.rs
@@ -25,6 +25,7 @@ pub const NULL_REVISION: Revision = -1;
 ///
 /// This is also equal to `i32::max_value()`, but it's better to spell
 /// it out explicitely, same as in `mercurial.node`
+#[allow(clippy::unreadable_literal)]
 pub const WORKING_DIRECTORY_REVISION: Revision = 0x7fffffff;
 
 /// The simplest expression of what we need of Mercurial DAGs.
@@ -49,6 +50,10 @@ pub trait RevlogIndex {
     /// Total number of Revisions referenced in this index
     fn len(&self) -> usize;
 
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     /// Return a reference to the Node or `None` if rev is out of bounds
     ///
     /// `NULL_REVISION` is not considered to be out of bounds.
diff --git a/rust/hg-core/src/revlog/node.rs b/rust/hg-core/src/revlog/node.rs
--- a/rust/hg-core/src/revlog/node.rs
+++ b/rust/hg-core/src/revlog/node.rs
@@ -208,6 +208,10 @@ impl<'a> NodePrefixRef<'a> {
         }
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     pub fn is_prefix_of(&self, node: &Node) -> bool {
         if self.is_odd {
             let buf = self.buf;
@@ -242,13 +246,13 @@ impl<'a> NodePrefixRef<'a> {
         } else {
             buf.len()
         };
-        for i in 0..until {
-            if buf[i] != node.data[i] {
-                if buf[i] & 0xf0 == node.data[i] & 0xf0 {
-                    return Some(2 * i + 1);
+        for (i, item) in buf.iter().enumerate().take(until) {
+            if *item != node.data[i] {
+                return if *item & 0xf0 == node.data[i] & 0xf0 {
+                    Some(2 * i + 1)
                 } else {
-                    return Some(2 * i);
-                }
+                    Some(2 * i)
+                };
             }
         }
         if self.is_odd && buf[until] & 0xf0 != node.data[until] & 0xf0 {
diff --git a/rust/hg-core/src/revlog/nodemap.rs b/rust/hg-core/src/revlog/nodemap.rs
--- a/rust/hg-core/src/revlog/nodemap.rs
+++ b/rust/hg-core/src/revlog/nodemap.rs
@@ -218,7 +218,7 @@ pub struct Block([u8; BLOCK_SIZE]);
 /// Not derivable for arrays of length >32 until const generics are stable
 impl PartialEq for Block {
     fn eq(&self, other: &Self) -> bool {
-        &self.0[..] == &other.0[..]
+        self.0[..] == other.0[..]
     }
 }
 
@@ -343,14 +343,11 @@ impl NodeTree {
     ///
     /// We keep `readonly` and clone its root block if it isn't empty.
     fn new(readonly: Box<dyn Deref<Target = [Block]> + Send>) -> Self {
-        let root = readonly
-            .last()
-            .map(|b| b.clone())
-            .unwrap_or_else(|| Block::new());
+        let root = readonly.last().cloned().unwrap_or_else(Block::new);
         NodeTree {
-            readonly: readonly,
+            readonly,
             growable: Vec::new(),
-            root: root,
+            root,
             masked_inner_blocks: 0,
         }
     }
@@ -461,7 +458,7 @@ impl NodeTree {
     ) -> NodeTreeVisitor<'n, 'p> {
         NodeTreeVisitor {
             nt: self,
-            prefix: prefix,
+            prefix,
             visit: self.len() - 1,
             nybble_idx: 0,
             done: false,
@@ -486,8 +483,7 @@ impl NodeTree {
         let glen = self.growable.len();
         if idx < ro_len {
             self.masked_inner_blocks += 1;
-            // TODO OPTIM I think this makes two copies
-            self.growable.push(ro_blocks[idx].clone());
+            self.growable.push(ro_blocks[idx]);
             (glen + ro_len, &mut self.growable[glen], glen + 1)
         } else if glen + ro_len == idx {
             (idx, &mut self.root, glen)
@@ -674,8 +670,8 @@ impl<'n, 'p> Iterator for NodeTreeVisito
 
         Some(NodeTreeVisitItem {
             block_idx: visit,
-            nybble: nybble,
-            element: element,
+            nybble,
+            element,
         })
     }
 }
diff --git a/rust/hg-core/src/utils.rs b/rust/hg-core/src/utils.rs
--- a/rust/hg-core/src/utils.rs
+++ b/rust/hg-core/src/utils.rs
@@ -68,6 +68,7 @@ pub trait SliceExt {
     fn drop_prefix(&self, needle: &Self) -> Option<&Self>;
 }
 
+#[allow(clippy::trivially_copy_pass_by_ref)]
 fn is_not_whitespace(c: &u8) -> bool {
     !(*c as char).is_whitespace()
 }
@@ -75,7 +76,7 @@ fn is_not_whitespace(c: &u8) -> bool {
 impl SliceExt for [u8] {
     fn trim_end(&self) -> &[u8] {
         if let Some(last) = self.iter().rposition(is_not_whitespace) {
-            &self[..last + 1]
+            &self[..=last]
         } else {
             &[]
         }
@@ -151,7 +152,7 @@ impl Escaped for u8 {
 
 impl<'a, T: Escaped> Escaped for &'a [T] {
     fn escaped_bytes(&self) -> Vec<u8> {
-        self.iter().flat_map(|item| item.escaped_bytes()).collect()
+        self.iter().flat_map(Escaped::escaped_bytes).collect()
     }
 }
 
diff --git a/rust/hg-core/src/utils/files.rs b/rust/hg-core/src/utils/files.rs
--- a/rust/hg-core/src/utils/files.rs
+++ b/rust/hg-core/src/utils/files.rs
@@ -98,7 +98,7 @@ impl<'a> FusedIterator for AncestorsWith
 ///
 /// The path itself isn't included unless it is b"" (meaning the root
 /// directory.)
-pub fn find_dirs<'a>(path: &'a HgPath) -> Ancestors<'a> {
+pub fn find_dirs(path: &HgPath) -> Ancestors {
     let mut dirs = Ancestors { next: Some(path) };
     if !path.is_empty() {
         dirs.next(); // skip itself
@@ -113,9 +113,7 @@ pub fn find_dirs<'a>(path: &'a HgPath) -
 ///
 /// The path itself isn't included unless it is b"" (meaning the root
 /// directory.)
-pub(crate) fn find_dirs_with_base<'a>(
-    path: &'a HgPath,
-) -> AncestorsWithBase<'a> {
+pub(crate) fn find_dirs_with_base(path: &HgPath) -> AncestorsWithBase {
     let mut dirs = AncestorsWithBase {
         next: Some((path, HgPath::new(b""))),
     };
@@ -214,9 +212,9 @@ pub fn canonical_path(
     if name != root && name.starts_with(&root) {
         let name = name.strip_prefix(&root).unwrap();
         auditor.audit_path(path_to_hg_path_buf(name)?)?;
-        return Ok(name.to_owned());
+        Ok(name.to_owned())
     } else if name == root {
-        return Ok("".into());
+        Ok("".into())
     } else {
         // Determine whether `name' is in the hierarchy at or beneath `root',
         // by iterating name=name.parent() until it returns `None` (can't
diff --git a/rust/hg-core/src/utils/hg_path.rs b/rust/hg-core/src/utils/hg_path.rs
--- a/rust/hg-core/src/utils/hg_path.rs
+++ b/rust/hg-core/src/utils/hg_path.rs
@@ -208,7 +208,7 @@ impl HgPath {
     }
     pub fn join<T: ?Sized + AsRef<Self>>(&self, other: &T) -> HgPathBuf {
         let mut inner = self.inner.to_owned();
-        if inner.len() != 0 && inner.last() != Some(&b'/') {
+        if !inner.is_empty() && inner.last() != Some(&b'/') {
             inner.push(b'/');
         }
         inner.extend(other.as_ref().bytes());
@@ -315,7 +315,7 @@ impl HgPath {
     /// This generates fine-grained errors useful for debugging.
     /// To simply check if the path is valid during tests, use `is_valid`.
     pub fn check_state(&self) -> Result<(), HgPathError> {
-        if self.len() == 0 {
+        if self.is_empty() {
             return Ok(());
         }
         let bytes = self.as_bytes();
@@ -366,14 +366,14 @@ impl fmt::Display for HgPath {
     }
 }
 
-#[derive(Eq, Ord, Clone, PartialEq, PartialOrd, Hash)]
+#[derive(Default, Eq, Ord, Clone, PartialEq, PartialOrd, Hash)]
 pub struct HgPathBuf {
     inner: Vec<u8>,
 }
 
 impl HgPathBuf {
     pub fn new() -> Self {
-        Self { inner: Vec::new() }
+        Default::default()
     }
     pub fn push(&mut self, byte: u8) {
         self.inner.push(byte);
@@ -384,9 +384,6 @@ impl HgPathBuf {
     pub fn into_vec(self) -> Vec<u8> {
         self.inner
     }
-    pub fn as_ref(&self) -> &[u8] {
-        self.inner.as_ref()
-    }
 }
 
 impl fmt::Debug for HgPathBuf {
diff --git a/rust/hg-core/src/utils/path_auditor.rs b/rust/hg-core/src/utils/path_auditor.rs
--- a/rust/hg-core/src/utils/path_auditor.rs
+++ b/rust/hg-core/src/utils/path_auditor.rs
@@ -112,7 +112,7 @@ impl PathAuditor {
         // accidentally traverse a symlink into some other filesystem (which
         // is potentially expensive to access).
         for index in 0..parts.len() {
-            let prefix = &parts[..index + 1].join(&b'/');
+            let prefix = &parts[..=index].join(&b'/');
             let prefix = HgPath::new(prefix);
             if self.audited_dirs.read().unwrap().contains(prefix) {
                 continue;
diff --git a/rust/hg-cpython/src/cindex.rs b/rust/hg-cpython/src/cindex.rs
--- a/rust/hg-cpython/src/cindex.rs
+++ b/rust/hg-cpython/src/cindex.rs
@@ -90,10 +90,7 @@ impl Index {
                 ),
             ));
         }
-        Ok(Index {
-            index: index,
-            capi: capi,
-        })
+        Ok(Index { index, capi })
     }
 
     /// return a reference to the CPython Index object in this Struct
@@ -158,7 +155,7 @@ impl RevlogIndex for Index {
         unsafe { (self.capi.index_length)(self.index.as_ptr()) as usize }
     }
 
-    fn node<'a>(&'a self, rev: Revision) -> Option<&'a Node> {
+    fn node(&self, rev: Revision) -> Option<&Node> {
         let raw = unsafe {
             (self.capi.index_node)(self.index.as_ptr(), rev as c_int)
         };
diff --git a/rust/hg-cpython/src/dirstate/copymap.rs b/rust/hg-cpython/src/dirstate/copymap.rs
--- a/rust/hg-cpython/src/dirstate/copymap.rs
+++ b/rust/hg-cpython/src/dirstate/copymap.rs
@@ -89,7 +89,7 @@ impl CopyMap {
         py: Python,
         res: (&HgPathBuf, &HgPathBuf),
     ) -> PyResult<Option<PyBytes>> {
-        Ok(Some(PyBytes::new(py, res.0.as_ref())))
+        Ok(Some(PyBytes::new(py, res.0.as_bytes())))
     }
     fn translate_key_value(
         py: Python,
@@ -97,8 +97,8 @@ impl CopyMap {
     ) -> PyResult<Option<(PyBytes, PyBytes)>> {
         let (k, v) = res;
         Ok(Some((
-            PyBytes::new(py, k.as_ref()),
-            PyBytes::new(py, v.as_ref()),
+            PyBytes::new(py, k.as_bytes()),
+            PyBytes::new(py, v.as_bytes()),
         )))
     }
 }
diff --git a/rust/hg-cpython/src/dirstate/dirs_multiset.rs b/rust/hg-cpython/src/dirstate/dirs_multiset.rs
--- a/rust/hg-cpython/src/dirstate/dirs_multiset.rs
+++ b/rust/hg-cpython/src/dirstate/dirs_multiset.rs
@@ -128,7 +128,7 @@ impl Dirs {
         py: Python,
         res: &HgPathBuf,
     ) -> PyResult<Option<PyBytes>> {
-        Ok(Some(PyBytes::new(py, res.as_ref())))
+        Ok(Some(PyBytes::new(py, res.as_bytes())))
     }
 }
 
diff --git a/rust/hg-cpython/src/dirstate/dirstate_map.rs b/rust/hg-cpython/src/dirstate/dirstate_map.rs
--- a/rust/hg-cpython/src/dirstate/dirstate_map.rs
+++ b/rust/hg-cpython/src/dirstate/dirstate_map.rs
@@ -179,7 +179,7 @@ py_class!(pub class DirstateMap |py| {
             "other_parent",
             other_parent
                 .iter()
-                .map(|v| PyBytes::new(py, v.as_ref()))
+                .map(|v| PyBytes::new(py, v.as_bytes()))
                 .collect::<Vec<PyBytes>>()
                 .to_py_object(py),
         )?;
@@ -348,7 +348,11 @@ py_class!(pub class DirstateMap |py| {
         for (key, value) in
             self.inner(py).borrow_mut().build_file_fold_map().iter()
         {
-            dict.set_item(py, key.as_ref().to_vec(), value.as_ref().to_vec())?;
+            dict.set_item(
+                py,
+                key.as_bytes().to_vec(),
+                value.as_bytes().to_vec(),
+            )?;
         }
         Ok(dict)
     }
@@ -440,8 +444,8 @@ py_class!(pub class DirstateMap |py| {
         for (key, value) in self.inner(py).borrow().copy_map.iter() {
             dict.set_item(
                 py,
-                PyBytes::new(py, key.as_ref()),
-                PyBytes::new(py, value.as_ref()),
+                PyBytes::new(py, key.as_bytes()),
+                PyBytes::new(py, value.as_bytes()),
             )?;
         }
         Ok(dict)
@@ -450,7 +454,7 @@ py_class!(pub class DirstateMap |py| {
     def copymapgetitem(&self, key: PyObject) -> PyResult<PyBytes> {
         let key = key.extract::<PyBytes>(py)?;
         match self.inner(py).borrow().copy_map.get(HgPath::new(key.data(py))) {
-            Some(copy) => Ok(PyBytes::new(py, copy.as_ref())),
+            Some(copy) => Ok(PyBytes::new(py, copy.as_bytes())),
             None => Err(PyErr::new::<exc::KeyError, _>(
                 py,
                 String::from_utf8_lossy(key.data(py)),
@@ -485,7 +489,7 @@ py_class!(pub class DirstateMap |py| {
             .get(HgPath::new(key.data(py)))
         {
             Some(copy) => Ok(Some(
-                PyBytes::new(py, copy.as_ref()).into_object(),
+                PyBytes::new(py, copy.as_bytes()).into_object(),
             )),
             None => Ok(default),
         }
@@ -549,7 +553,7 @@ impl DirstateMap {
         py: Python,
         res: (&HgPathBuf, &DirstateEntry),
     ) -> PyResult<Option<PyBytes>> {
-        Ok(Some(PyBytes::new(py, res.0.as_ref())))
+        Ok(Some(PyBytes::new(py, res.0.as_bytes())))
     }
     fn translate_key_value(
         py: Python,
@@ -557,7 +561,7 @@ impl DirstateMap {
     ) -> PyResult<Option<(PyBytes, PyObject)>> {
         let (f, entry) = res;
         Ok(Some((
-            PyBytes::new(py, f.as_ref()),
+            PyBytes::new(py, f.as_bytes()),
             make_dirstate_tuple(py, entry)?,
         )))
     }
diff --git a/rust/hg-cpython/src/dirstate/non_normal_entries.rs b/rust/hg-cpython/src/dirstate/non_normal_entries.rs
--- a/rust/hg-cpython/src/dirstate/non_normal_entries.rs
+++ b/rust/hg-cpython/src/dirstate/non_normal_entries.rs
@@ -62,7 +62,7 @@ impl NonNormalEntries {
         py: Python,
         key: &HgPathBuf,
     ) -> PyResult<Option<PyBytes>> {
-        Ok(Some(PyBytes::new(py, key.as_ref())))
+        Ok(Some(PyBytes::new(py, key.as_bytes())))
     }
 }
 
diff --git a/rust/hg-cpython/src/dirstate/status.rs b/rust/hg-cpython/src/dirstate/status.rs
--- a/rust/hg-cpython/src/dirstate/status.rs
+++ b/rust/hg-cpython/src/dirstate/status.rs
@@ -236,12 +236,10 @@ pub fn status_wrapper(
 
             build_response(py, lookup, status_res, all_warnings)
         }
-        e => {
-            return Err(PyErr::new::<ValueError, _>(
-                py,
-                format!("Unsupported matcher {}", e),
-            ));
-        }
+        e => Err(PyErr::new::<ValueError, _>(
+            py,
+            format!("Unsupported matcher {}", e),
+        )),
     }
 }
 
diff --git a/rust/hg-cpython/src/parsers.rs b/rust/hg-cpython/src/parsers.rs
--- a/rust/hg-cpython/src/parsers.rs
+++ b/rust/hg-cpython/src/parsers.rs
@@ -37,15 +37,15 @@ fn parse_dirstate_wrapper(
             for (filename, entry) in &dirstate_map {
                 dmap.set_item(
                     py,
-                    PyBytes::new(py, filename.as_ref()),
+                    PyBytes::new(py, filename.as_bytes()),
                     make_dirstate_tuple(py, entry)?,
                 )?;
             }
             for (path, copy_path) in copies {
                 copymap.set_item(
                     py,
-                    PyBytes::new(py, path.as_ref()),
-                    PyBytes::new(py, copy_path.as_ref()),
+                    PyBytes::new(py, path.as_bytes()),
+                    PyBytes::new(py, copy_path.as_bytes()),
                 )?;
             }
             Ok(
@@ -116,7 +116,7 @@ fn pack_dirstate_wrapper(
             for (filename, entry) in &dirstate_map {
                 dmap.set_item(
                     py,
-                    PyBytes::new(py, filename.as_ref()),
+                    PyBytes::new(py, filename.as_bytes()),
                     make_dirstate_tuple(py, entry)?,
                 )?;
             }
diff --git a/rust/hg-cpython/src/utils.rs b/rust/hg-cpython/src/utils.rs
--- a/rust/hg-cpython/src/utils.rs
+++ b/rust/hg-cpython/src/utils.rs
@@ -32,10 +32,7 @@ pub fn node_from_py_object<'a>(
 
 /// Clone incoming Python bytes given as `PyBytes` as a `Node`,
 /// doing the necessary checks.
-pub fn node_from_py_bytes<'a>(
-    py: Python,
-    bytes: &'a PyBytes,
-) -> PyResult<Node> {
+pub fn node_from_py_bytes(py: Python, bytes: &PyBytes) -> PyResult<Node> {
     <NodeData>::try_from(bytes.data(py))
         .map_err(|_| {
             PyErr::new::<ValueError, _>(
@@ -43,5 +40,5 @@ pub fn node_from_py_bytes<'a>(
                 format!("{}-byte hash required", NODE_BYTES_LENGTH),
             )
         })
-        .map(|n| n.into())
+        .map(Into::into)
 }