refactor: address Clippy warnings

src/document.rs

@@ -11,14 +11,17 @@ pub struct Document {
 }
 
 impl Document {
+    #[must_use]
     pub fn row(&self, index: usize) -> Option<&Row> {
         self.rows.get(index)
     }
 
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         self.rows.is_empty()
     }
 
+    #[must_use]
     pub fn len(&self) -> usize {
         self.rows.len()
     }
@@ -35,6 +38,9 @@ impl Document {
         self.rows.insert(at.y + 1, new_row);
     }
 
+    /// # Panics
+    /// This function can panic if the given Position is not
+    /// within the document's rows.
     pub fn insert(&mut self, at: &Position, c: char) {
         if c == '\n' {
             self.insert_newline(at);
@@ -54,6 +60,9 @@ impl Document {
         }
     }
 
+    /// # Panics
+    /// This function can panic if the given Position is not
+    /// within the document's rows.
     pub fn delete(&mut self, at: &Position) {
         let len = self.len();
         if at.y >= len {
@@ -69,6 +78,8 @@ impl Document {
         }
     }
 
+    /// # Errors
+    /// Returns an error if the file could not be opened.
     pub fn open(filename: &str) -> Result<Self, std::io::Error> {
         let contents = fs::read_to_string(filename)?;
         let mut rows = vec![];
@@ -81,6 +92,8 @@ impl Document {
         })
     }
 
+    /// # Errors
+    /// Returns an error if the file could not be saved.
     pub fn save(&self) -> Result<(), Error> {
         if let Some(file_name) = &self.file_name {
             let mut file = fs::File::create(file_name)?;

src/editor.rs

@@ -70,13 +70,13 @@ impl Editor {
     pub fn run(&mut self) {
         loop {
             if let Err(error) = self.refresh_screen() {
-                die(error);
+                die(&error);
             };
             if self.should_quit {
                 break;
             }
             if let Err(error) = self.process_keypress() {
-                die(error);
+                die(&error);
             };
         }
     }
@@ -276,7 +276,7 @@ impl Editor {
     fn draw_message_bar(&self) {
         Terminal::clear_current_line();
         let message = &self.status_message;
-        if Instant::now() - message.time < Duration::new(5, 0) {
+        if message.time.elapsed() < Duration::new(5, 0) {
             let mut text = message.text.clone();
             text.truncate(self.terminal.size().width as usize);
             print!("{}", text);
@@ -284,7 +284,7 @@ impl Editor {
     }
 }
 
-fn die(e: std::io::Error) {
+fn die(e: &std::io::Error) {
     Terminal::clear_screen();
     panic!("{}", e);
 }

src/main.rs

@@ -8,10 +8,8 @@ use crate::editor::Editor;
 pub use crate::editor::Position;
 pub use crate::row::Row;
 pub use crate::terminal::Terminal;
-use anyhow::Result;
 
-fn main() -> Result<()> {
+fn main() {
     let mut editor = Editor::default();
     editor.run();
-    Ok(())
 }

src/row.rs

@@ -19,6 +19,7 @@ impl From<&str> for Row {
 }
 
 impl Row {
+    #[must_use]
     pub fn render(&self, start: usize, end: usize) -> String {
         let end = cmp::min(end, self.contents.len());
         let start = cmp::min(start, end);
@@ -37,10 +38,12 @@ impl Row {
         result
     }
 
+    #[must_use]
     pub fn len(&self) -> usize {
         self.len
     }
 
+    #[must_use]
     pub fn is_empty(&self) -> bool {
         self.len == 0
     }
@@ -65,12 +68,11 @@ impl Row {
     pub fn delete(&mut self, at: usize) {
         if at >= self.len() {
             return;
-        } else {
-            let mut result: String = self.contents[..].graphemes(true).take(at).collect();
-            let remainder: String = self.contents[..].graphemes(true).skip(at + 1).collect();
-            result.push_str(&remainder);
-            self.contents = result;
         }
+        let mut result: String = self.contents[..].graphemes(true).take(at).collect();
+        let remainder: String = self.contents[..].graphemes(true).skip(at + 1).collect();
+        result.push_str(&remainder);
+        self.contents = result;
         self.update_len();
     }
 
@@ -79,6 +81,7 @@ impl Row {
         self.update_len();
     }
 
+    #[must_use]
     pub fn split(&mut self, at: usize) -> Self {
         let beginning: String = self.contents[..].graphemes(true).take(at).collect();
         let remainder: String = self.contents[..].graphemes(true).skip(at).collect();
@@ -87,6 +90,7 @@ impl Row {
         Self::from(&remainder[..])
     }
 
+    #[must_use]
     pub fn as_bytes(&self) -> &[u8] {
         self.contents.as_bytes()
     }

src/terminal.rs

@@ -16,6 +16,8 @@ pub struct Terminal {
 }
 
 impl Terminal {
+    /// # Errors
+    /// Returns an error if terminal size cannot be retrieved or raw mode cannot be enabled.
     pub fn default() -> Result<Self, Error> {
         let size = termion::terminal_size()?;
         Ok(Self {
@@ -27,6 +29,7 @@ impl Terminal {
         })
     }
 
+    #[must_use]
     pub fn size(&self) -> &Size {
         &self.size
     }
@@ -39,6 +42,7 @@ impl Terminal {
         print!("{}", termion::clear::CurrentLine);
     }
 
+    #[allow(clippy::cast_possible_truncation)]
     pub fn reposition_cursor(position: &Position) {
         let Position { mut x, mut y } = position;
         x = x.saturating_add(1);
@@ -48,10 +52,14 @@ impl Terminal {
         print!("{}", termion::cursor::Goto(x, y));
     }
 
+    /// # Errors
+    /// Returns an error if stdout cannot be flushed
     pub fn flush() -> Result<(), Error> {
         io::stdout().flush()
     }
 
+    /// # Errors
+    /// Returns an error if input events can't be retrieved
     pub fn read_key() -> Result<Key, io::Error> {
         loop {
             if let Some(key) = io::stdin().lock().keys().next() {