various refactorings (#909)

* ran `cargo clippy --fix -- -Wclippy::use_self`

* refactoring

* refactored counting functions to use `std::iter::successors`

src/diff/dijkstra.rs

@@ -156,33 +156,20 @@ fn edge_between<'s, 'v>(before: &Vertex<'s, 'v>, after: &Vertex<'s, 'v>) -> Edge
 
 /// What is the total number of AST nodes?
 fn node_count(root: Option<&Syntax>) -> u32 {
-    let mut node = root;
-    let mut count = 0;
-    while let Some(current_node) = node {
-        let current_count = match current_node {
-            Syntax::List {
-                num_descendants, ..
-            } => *num_descendants,
-            Syntax::Atom { .. } => 1,
-        };
-        count += current_count;
-
-        node = current_node.next_sibling();
-    }
-
-    count
+    let iter = std::iter::successors(root, |node| node.next_sibling());
+
+    iter.map(|node| match node {
+        Syntax::List {
+            num_descendants, ..
+        } => *num_descendants,
+        Syntax::Atom { .. } => 1,
+    })
+    .sum::<u32>()
 }
 
 /// How many top-level AST nodes do we have?
 fn tree_count(root: Option<&Syntax>) -> u32 {
-    let mut node = root;
-    let mut count = 0;
-    while let Some(current_node) = node {
-        count += 1;
-        node = current_node.next_sibling();
-    }
-
-    count
+    std::iter::successors(root, |node| node.next_sibling()).count() as _
 }
 
 pub(crate) fn mark_syntax<'a>(

src/diff/graph.rs

@@ -138,14 +138,14 @@ enum EnteredDelimiter<'s, 'v> {
 impl fmt::Debug for EnteredDelimiter<'_, '_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let desc = match self {
-            EnteredDelimiter::PopEither((lhs_delims, rhs_delims)) => {
+            Self::PopEither((lhs_delims, rhs_delims)) => {
                 format!(
                     "PopEither(lhs count: {}, rhs count: {})",
                     lhs_delims.size(),
                     rhs_delims.size()
                 )
             }
-            EnteredDelimiter::PopBoth(_) => "PopBoth".to_owned(),
+            Self::PopBoth(_) => "PopBoth".to_owned(),
         };
         f.write_str(&desc)
     }

src/diff/stack.rs

@@ -24,11 +24,11 @@ impl<'b, T> Stack<'b, T> {
         self.head.map(|n| &n.val)
     }
 
-    pub(crate) fn pop(&self) -> Option<Stack<'b, T>> {
+    pub(crate) fn pop(&self) -> Option<Self> {
         self.head.map(|n| Self { head: n.next })
     }
 
-    pub(crate) fn push(&self, v: T, alloc: &'b Bump) -> Stack<'b, T> {
+    pub(crate) fn push(&self, v: T, alloc: &'b Bump) -> Self {
         Self {
             head: Some(alloc.alloc(Node {
                 val: v,
@@ -39,13 +39,7 @@ impl<'b, T> Stack<'b, T> {
 
     // O(n)
     pub(crate) fn size(&self) -> usize {
-        let mut count = 0;
-        let mut node = &self.head;
-        while let Some(next) = node {
-            count += 1;
-            node = &next.next;
-        }
-        count
+        std::iter::successors(self.head, |&n| n.next).count()
     }
 
     pub(crate) fn is_empty(&self) -> bool {

src/display/hunks.rs

@@ -66,7 +66,7 @@ impl Hunk {
             ));
         }
 
-        Hunk {
+        Self {
             novel_lhs: self.novel_lhs.union(&other.novel_lhs).copied().collect(),
             novel_rhs: self.novel_rhs.union(&other.novel_rhs).copied().collect(),
             lines: deduped_lines,

src/display/json.rs

@@ -32,11 +32,7 @@ struct File<'f> {
 }
 
 impl<'f> File<'f> {
-    fn with_sections(
-        language: &'f FileFormat,
-        path: &'f str,
-        chunks: Vec<Vec<Line<'f>>>,
-    ) -> File<'f> {
+    fn with_sections(language: &'f FileFormat, path: &'f str, chunks: Vec<Vec<Line<'f>>>) -> Self {
         File {
             language,
             path,
@@ -45,7 +41,7 @@ impl<'f> File<'f> {
         }
     }
 
-    fn with_status(language: &'f FileFormat, path: &'f str, status: Status) -> File<'f> {
+    fn with_status(language: &'f FileFormat, path: &'f str, status: Status) -> Self {
         File {
             language,
             path,
@@ -201,7 +197,7 @@ struct Line<'l> {
 }
 
 impl<'l> Line<'l> {
-    fn new(lhs_number: Option<u32>, rhs_number: Option<u32>) -> Line<'l> {
+    fn new(lhs_number: Option<u32>, rhs_number: Option<u32>) -> Self {
         Line {
             lhs: lhs_number.map(Side::new),
             rhs: rhs_number.map(Side::new),
@@ -216,7 +212,7 @@ struct Side<'s> {
 }
 
 impl<'s> Side<'s> {
-    fn new(line_number: u32) -> Side<'s> {
+    fn new(line_number: u32) -> Self {
         Side {
             line_number,
             changes: Vec::new(),
@@ -259,15 +255,15 @@ impl Highlight {
         };
 
         match highlight {
-            TokenKind::Delimiter => Highlight::Delimiter,
+            TokenKind::Delimiter => Self::Delimiter,
             TokenKind::Atom(atom) => match atom {
-                AtomKind::String(StringKind::StringLiteral) => Highlight::String,
-                AtomKind::String(StringKind::Text) => Highlight::Normal,
-                AtomKind::Keyword => Highlight::Keyword,
-                AtomKind::Comment => Highlight::Comment,
-                AtomKind::Type => Highlight::Type,
-                AtomKind::Normal => Highlight::Normal,
-                AtomKind::TreeSitterError => Highlight::TreeSitterError,
+                AtomKind::String(StringKind::StringLiteral) => Self::String,
+                AtomKind::String(StringKind::Text) => Self::Normal,
+                AtomKind::Keyword => Self::Keyword,
+                AtomKind::Comment => Self::Comment,
+                AtomKind::Type => Self::Type,
+                AtomKind::Normal => Self::Normal,
+                AtomKind::TreeSitterError => Self::TreeSitterError,
             },
         }
     }

src/display/style.rs

@@ -26,7 +26,7 @@ pub(crate) enum BackgroundColor {
 
 impl BackgroundColor {
     pub(crate) fn is_dark(self) -> bool {
-        matches!(self, BackgroundColor::Dark)
+        matches!(self, Self::Dark)
     }
 }
 

src/options.rs

@@ -398,7 +398,7 @@ pub(crate) enum FileArgument {
 impl FileArgument {
     pub(crate) fn permissions(&self) -> Option<FilePermissions> {
         match self {
-            FileArgument::NamedPath(path) => {
+            Self::NamedPath(path) => {
                 // When used with `git difftool`, the first argument
                 // is a temporary file that always has the same
                 // permissions. That doesn't mean the file permissions
@@ -410,8 +410,8 @@ impl FileArgument {
                 let metadata = std::fs::metadata(path).ok()?;
                 Some(metadata.permissions().into())
             }
-            FileArgument::Stdin => None,
-            FileArgument::DevNull => None,
+            Self::Stdin => None,
+            Self::DevNull => None,
         }
     }
 }
@@ -484,11 +484,11 @@ impl FileArgument {
     /// argument.
     pub(crate) fn from_cli_argument(arg: &OsStr) -> Self {
         if arg == "/dev/null" {
-            FileArgument::DevNull
+            Self::DevNull
         } else if arg == "-" {
-            FileArgument::Stdin
+            Self::Stdin
         } else {
-            FileArgument::NamedPath(PathBuf::from(arg))
+            Self::NamedPath(PathBuf::from(arg))
         }
     }
 
@@ -497,9 +497,9 @@ impl FileArgument {
     pub(crate) fn from_path_argument(arg: &OsStr) -> Self {
         // For new and deleted files, Git passes `/dev/null` as the reference file.
         if arg == "/dev/null" {
-            FileArgument::DevNull
+            Self::DevNull
         } else {
-            FileArgument::NamedPath(PathBuf::from(arg))
+            Self::NamedPath(PathBuf::from(arg))
         }
     }
 }
@@ -507,11 +507,11 @@ impl FileArgument {
 impl Display for FileArgument {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            FileArgument::NamedPath(path) => {
+            Self::NamedPath(path) => {
                 write!(f, "{}", relative_to_current(path).display())
             }
-            FileArgument::Stdin => write!(f, "(stdin)"),
-            FileArgument::DevNull => write!(f, "/dev/null"),
+            Self::Stdin => write!(f, "(stdin)"),
+            Self::DevNull => write!(f, "/dev/null"),
         }
     }
 }

src/parse/guess_language.rs

@@ -525,54 +525,51 @@ fn from_emacs_mode_header(src: &str) -> Option<Language> {
             (Some(cap), _) | (_, Some(cap)) => cap[1].into(),
             _ => "".into(),
         };
-        let lang = match mode_name.to_ascii_lowercase().trim() {
-            "ada" => Some(Ada),
-            "c" => Some(C),
-            "clojure" => Some(Clojure),
-            "csharp" => Some(CSharp),
-            "css" => Some(Css),
-            "dart" => Some(Dart),
-            "c++" => Some(CPlusPlus),
-            "elixir" => Some(Elixir),
-            "elm" => Some(Elm),
-            "elvish" => Some(Elvish),
-            "emacs-lisp" => Some(EmacsLisp),
-            "fsharp" => Some(FSharp),
-            "gleam" => Some(Gleam),
-            "go" => Some(Go),
-            "haskell" => Some(Haskell),
-            "hcl" => Some(Hcl),
-            "html" => Some(Html),
-            "janet" => Some(Janet),
-            "java" => Some(Java),
-            "js" | "js2" => Some(JavaScript),
-            "lisp" => Some(CommonLisp),
-            "nxml" => Some(Xml),
-            "objc" => Some(ObjC),
-            "perl" => Some(Perl),
-            "python" => Some(Python),
-            "racket" => Some(Racket),
-            "rjsx" => Some(JavascriptJsx),
-            "ruby" => Some(Ruby),
-            "rust" => Some(Rust),
-            "scala" => Some(Scala),
-            "scss" => Some(Scss),
-            "sh" => Some(Bash),
-            "solidity" => Some(Solidity),
-            "sql" => Some(Sql),
-            "swift" => Some(Swift),
-            "toml" => Some(Toml),
-            "tuareg" => Some(OCaml),
-            "typescript" => Some(TypeScript),
-            "verilog" => Some(Verilog),
-            "vhdl" => Some(Vhdl),
-            "yaml" => Some(Yaml),
-            "zig" => Some(Zig),
-            _ => None,
-        };
-        if lang.is_some() {
-            return lang;
-        }
+        return Some(match mode_name.to_ascii_lowercase().trim() {
+            "ada" => Ada,
+            "c" => C,
+            "clojure" => Clojure,
+            "csharp" => CSharp,
+            "css" => Css,
+            "dart" => Dart,
+            "c++" => CPlusPlus,
+            "elixir" => Elixir,
+            "elm" => Elm,
+            "elvish" => Elvish,
+            "emacs-lisp" => EmacsLisp,
+            "fsharp" => FSharp,
+            "gleam" => Gleam,
+            "go" => Go,
+            "haskell" => Haskell,
+            "hcl" => Hcl,
+            "html" => Html,
+            "janet" => Janet,
+            "java" => Java,
+            "js" | "js2" => JavaScript,
+            "lisp" => CommonLisp,
+            "nxml" => Xml,
+            "objc" => ObjC,
+            "perl" => Perl,
+            "python" => Python,
+            "racket" => Racket,
+            "rjsx" => JavascriptJsx,
+            "ruby" => Ruby,
+            "rust" => Rust,
+            "scala" => Scala,
+            "scss" => Scss,
+            "sh" => Bash,
+            "solidity" => Solidity,
+            "sql" => Sql,
+            "swift" => Swift,
+            "toml" => Toml,
+            "tuareg" => OCaml,
+            "typescript" => TypeScript,
+            "verilog" => Verilog,
+            "vhdl" => Vhdl,
+            "yaml" => Yaml,
+            "zig" => Zig,
+            _ => continue,
+        });
     }
 
     None

src/parse/syntax.rs

@@ -196,13 +196,13 @@ impl<'a> fmt::Debug for Syntax<'a> {
 
 impl<'a> Syntax<'a> {
     pub(crate) fn new_list(
-        arena: &'a Arena<Syntax<'a>>,
+        arena: &'a Arena<Self>,
         open_content: &str,
         open_position: Vec<SingleLineSpan>,
-        children: Vec<&'a Syntax<'a>>,
+        children: Vec<&'a Self>,
         close_content: &str,
         close_position: Vec<SingleLineSpan>,
-    ) -> &'a Syntax<'a> {
+    ) -> &'a Self {
         // Skip empty atoms: they aren't displayed, so there's no
         // point making our syntax tree bigger. These occur when we're
         // parsing incomplete or malformed programs.
@@ -249,11 +249,11 @@ impl<'a> Syntax<'a> {
     }
 
     pub(crate) fn new_atom(
-        arena: &'a Arena<Syntax<'a>>,
+        arena: &'a Arena<Self>,
         mut position: Vec<SingleLineSpan>,
         mut content: String,
         kind: AtomKind,
-    ) -> &'a Syntax<'a> {
+    ) -> &'a Self {
         // If a parser hasn't cleaned up \r on CRLF files with
         // comments, discard it.
         if content.ends_with('\r') {
@@ -283,11 +283,11 @@ impl<'a> Syntax<'a> {
         }
     }
 
-    pub(crate) fn parent(&self) -> Option<&'a Syntax<'a>> {
+    pub(crate) fn parent(&self) -> Option<&'a Self> {
         self.info().parent.get()
     }
 
-    pub(crate) fn next_sibling(&self) -> Option<&'a Syntax<'a>> {
+    pub(crate) fn next_sibling(&self) -> Option<&'a Self> {
         self.info().next_sibling.get()
     }
 
@@ -681,9 +681,7 @@ impl MatchKind {
     pub(crate) fn is_novel(&self) -> bool {
         matches!(
             self,
-            MatchKind::Novel { .. }
-                | MatchKind::NovelWord { .. }
-                | MatchKind::UnchangedPartOfNovelItem { .. }
+            Self::Novel { .. } | Self::NovelWord { .. } | Self::UnchangedPartOfNovelItem { .. }
         )
     }
 }

src/summary.rs

@@ -27,10 +27,10 @@ pub(crate) enum FileFormat {
 impl Display for FileFormat {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            FileFormat::SupportedLanguage(language) => write!(f, "{}", language_name(*language)),
-            FileFormat::PlainText => write!(f, "Text"),
-            FileFormat::TextFallback { reason } => write!(f, "Text ({})", reason),
-            FileFormat::Binary => write!(f, "Binary"),
+            Self::SupportedLanguage(language) => write!(f, "{}", language_name(*language)),
+            Self::PlainText => write!(f, "Text"),
+            Self::TextFallback { reason } => write!(f, "Text ({})", reason),
+            Self::Binary => write!(f, "Binary"),
         }
     }
 }