style: address many Clippy lints

thaliaarchi · web-flow · commit da0008884062 · 2025-04-05T07:27:48.000-04:00
PR BurntSushi#392
diff --git a/csv-core/src/lib.rs b/csv-core/src/lib.rs
@@ -114,10 +114,11 @@ mod writer;
 ///
 /// Use this to specify the record terminator while parsing CSV. The default is
 /// CRLF, which treats `\r`, `\n` or `\r\n` as a single record terminator.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Default)]
 #[non_exhaustive]
 pub enum Terminator {
     /// Parses `\r`, `\n` or `\r\n` as a single record terminator.
+    #[default]
     CRLF,
     /// Parses the byte given as a record terminator.
     Any(u8),
@@ -140,14 +141,8 @@ impl Terminator {
     }
 }
 
-impl Default for Terminator {
-    fn default() -> Terminator {
-        Terminator::CRLF
-    }
-}
-
 /// The quoting style to use when writing CSV data.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Default)]
 #[non_exhaustive]
 pub enum QuoteStyle {
     /// This puts quotes around every field. Always.
@@ -159,6 +154,7 @@ pub enum QuoteStyle {
     /// (which is indistinguishable from a record with one empty field).
     ///
     /// This is the default.
+    #[default]
     Necessary,
     /// This puts quotes around all fields that are non-numeric. Namely, when
     /// writing a field that does not parse as a valid float or integer, then
@@ -167,9 +163,3 @@ pub enum QuoteStyle {
     /// This *never* writes quotes, even if it would produce invalid CSV data.
     Never,
 }
-
-impl Default for QuoteStyle {
-    fn default() -> QuoteStyle {
-        QuoteStyle::Necessary
-    }
-}
diff --git a/csv-core/src/reader.rs b/csv-core/src/reader.rs
@@ -439,7 +439,7 @@ enum NfaState {
 }
 
 /// A list of NFA states that have an explicit representation in the DFA.
-const NFA_STATES: &'static [NfaState] = &[
+const NFA_STATES: &[NfaState] = &[
     NfaState::StartRecord,
     NfaState::StartField,
     NfaState::EndFieldDelim,
@@ -455,21 +455,18 @@ const NFA_STATES: &'static [NfaState] = &[
 impl NfaState {
     /// Returns true if this state indicates that a field has been parsed.
     fn is_field_final(&self) -> bool {
-        match *self {
+        matches!(
+            *self,
             NfaState::End
-            | NfaState::EndRecord
-            | NfaState::CRLF
-            | NfaState::EndFieldDelim => true,
-            _ => false,
-        }
+                | NfaState::EndRecord
+                | NfaState::CRLF
+                | NfaState::EndFieldDelim
+        )
     }
 
     /// Returns true if this state indicates that a record has been parsed.
     fn is_record_final(&self) -> bool {
-        match *self {
-            NfaState::End | NfaState::EndRecord | NfaState::CRLF => true,
-            _ => false,
-        }
+        matches!(*self, NfaState::End | NfaState::EndRecord | NfaState::CRLF)
     }
 }
 
@@ -1238,11 +1235,11 @@ impl DfaClasses {
             panic!("added too many classes")
         }
         self.classes[b as usize] = self.next_class as u8;
-        self.next_class = self.next_class + 1;
+        self.next_class += 1;
     }
 
     fn num_classes(&self) -> usize {
-        self.next_class as usize
+        self.next_class
     }
 
     /// Scan and copy the input bytes to the output buffer quickly.
diff --git a/csv-core/src/writer.rs b/csv-core/src/writer.rs
@@ -28,7 +28,7 @@ impl WriterBuilder {
             double_quote: true,
             comment: None,
         };
-        WriterBuilder { wtr: wtr }
+        WriterBuilder { wtr }
     }
 
     /// Builder a CSV writer from this configuration.
@@ -189,13 +189,9 @@ pub struct Writer {
 
 impl Clone for Writer {
     fn clone(&self) -> Writer {
-        let mut requires_quotes = [false; 256];
-        for i in 0..256 {
-            requires_quotes[i] = self.requires_quotes[i];
-        }
         Writer {
             state: self.state.clone(),
-            requires_quotes: requires_quotes,
+            requires_quotes: self.requires_quotes,
             delimiter: self.delimiter,
             term: self.term,
             style: self.style,
@@ -393,7 +389,7 @@ impl Writer {
             self.state.quoting = false;
         }
         let (res, o) = match self.term {
-            Terminator::CRLF => write_pessimistic(&[b'\r', b'\n'], output),
+            Terminator::CRLF => write_pessimistic(b"\r\n", output),
             Terminator::Any(b) => write_pessimistic(&[b], output),
         };
         if o == 0 {
@@ -515,7 +511,7 @@ pub fn is_non_numeric(input: &[u8]) -> bool {
     // I suppose this could be faster if we wrote validators of numbers instead
     // of using the actual parser, but that's probably a lot of work for a bit
     // of a niche feature.
-    !s.parse::<f64>().is_ok() && !s.parse::<i128>().is_ok()
+    s.parse::<f64>().is_err() && s.parse::<i128>().is_err()
 }
 
 /// Escape quotes `input` and writes the result to `output`.
diff --git a/src/byte_record.rs b/src/byte_record.rs
@@ -698,7 +698,7 @@ impl Bounds {
     /// If there are no fields, this returns `0`.
     #[inline]
     fn end(&self) -> usize {
-        self.ends().last().map(|&i| i).unwrap_or(0)
+        self.ends().last().copied().unwrap_or(0)
     }
 
     /// Returns the number of fields in these bounds.
diff --git a/src/debug.rs b/src/debug.rs
@@ -50,9 +50,9 @@ impl<'a> core::fmt::Debug for Bytes<'a> {
 pub(crate) fn utf8_decode(bytes: &[u8]) -> Option<Result<char, u8>> {
     fn len(byte: u8) -> Option<usize> {
         if byte <= 0x7F {
-            return Some(1);
+            Some(1)
         } else if byte & 0b1100_0000 == 0b1000_0000 {
-            return None;
+            None
         } else if byte <= 0b1101_1111 {
             Some(2)
         } else if byte <= 0b1110_1111 {
diff --git a/src/deserializer.rs b/src/deserializer.rs
@@ -29,7 +29,7 @@ pub fn deserialize_string_record<'de, D: Deserialize<'de>>(
     });
     D::deserialize(&mut deser).map_err(|err| {
         Error::new(ErrorKind::Deserialize {
-            pos: record.position().map(Clone::clone),
+            pos: record.position().cloned(),
             err,
         })
     })
@@ -46,7 +46,7 @@ pub fn deserialize_byte_record<'de, D: Deserialize<'de>>(
     });
     D::deserialize(&mut deser).map_err(|err| {
         Error::new(ErrorKind::Deserialize {
-            pos: record.position().map(Clone::clone),
+            pos: record.position().cloned(),
             err,
         })
     })
@@ -284,7 +284,7 @@ impl<'r> DeRecord<'r> for DeByteRecord<'r> {
 
     #[inline]
     fn peek_field(&mut self) -> Option<&'r [u8]> {
-        self.it.peek().map(|s| *s)
+        self.it.peek().copied()
     }
 
     fn error(&self, kind: DeserializeErrorKind) -> DeserializeError {
@@ -329,8 +329,8 @@ macro_rules! deserialize_int {
             visitor: V,
         ) -> Result<V::Value, Self::Error> {
             let field = self.next_field()?;
-            let num = if field.starts_with("0x") {
-                <$inttype>::from_str_radix(&field[2..], 16)
+            let num = if let Some(digits) = field.strip_prefix("0x") {
+                <$inttype>::from_str_radix(digits, 16)
             } else {
                 field.parse()
             };
@@ -425,7 +425,7 @@ impl<'a, 'de: 'a, T: DeRecord<'de>> Deserializer<'de>
         self,
         visitor: V,
     ) -> Result<V::Value, Self::Error> {
-        self.next_field().and_then(|f| visitor.visit_str(f.into()))
+        self.next_field().and_then(|f| visitor.visit_str(f))
     }
 
     fn deserialize_bytes<V: Visitor<'de>>(
@@ -449,7 +449,7 @@ impl<'a, 'de: 'a, T: DeRecord<'de>> Deserializer<'de>
     ) -> Result<V::Value, Self::Error> {
         match self.peek_field() {
             None => visitor.visit_none(),
-            Some(f) if f.is_empty() => {
+            Some([]) => {
                 self.next_field().expect("empty field");
                 visitor.visit_none()
             }
diff --git a/src/error.rs b/src/error.rs
@@ -40,10 +40,7 @@ impl Error {
     /// If this is true, the underlying `ErrorKind` is guaranteed to be
     /// `ErrorKind::Io`.
     pub fn is_io_error(&self) -> bool {
-        match *self.0 {
-            ErrorKind::Io(_) => true,
-            _ => false,
-        }
+        matches!(*self.0, ErrorKind::Io(_))
     }
 
     /// Return the position for this error, if one exists.
diff --git a/src/lib.rs b/src/lib.rs
@@ -166,7 +166,7 @@ pub mod tutorial;
 mod writer;
 
 /// The quoting style to use when writing CSV data.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Default)]
 #[non_exhaustive]
 pub enum QuoteStyle {
     /// This puts quotes around every field. Always.
@@ -178,6 +178,7 @@ pub enum QuoteStyle {
     /// (which is indistinguishable from a record with one empty field).
     ///
     /// This is the default.
+    #[default]
     Necessary,
     /// This puts quotes around all fields that are non-numeric. Namely, when
     /// writing a field that does not parse as a valid float or integer, then
@@ -198,20 +199,15 @@ impl QuoteStyle {
     }
 }
 
-impl Default for QuoteStyle {
-    fn default() -> QuoteStyle {
-        QuoteStyle::Necessary
-    }
-}
-
 /// A record terminator.
 ///
 /// Use this to specify the record terminator while parsing CSV. The default is
 /// CRLF, which treats `\r`, `\n` or `\r\n` as a single record terminator.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, Default)]
 #[non_exhaustive]
 pub enum Terminator {
     /// Parses `\r`, `\n` or `\r\n` as a single record terminator.
+    #[default]
     CRLF,
     /// Parses the byte given as a record terminator.
     Any(u8),
@@ -227,17 +223,12 @@ impl Terminator {
     }
 }
 
-impl Default for Terminator {
-    fn default() -> Terminator {
-        Terminator::CRLF
-    }
-}
-
 /// The whitespace preservation behaviour when reading CSV data.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, PartialEq)]
 #[non_exhaustive]
 pub enum Trim {
     /// Preserves fields and headers. This is the default.
+    #[default]
     None,
     /// Trim whitespace from headers.
     Headers,
@@ -257,12 +248,6 @@ impl Trim {
     }
 }
 
-impl Default for Trim {
-    fn default() -> Trim {
-        Trim::None
-    }
-}
-
 /// A custom Serde deserializer for possibly invalid `Option<T>` fields.
 ///
 /// When deserializing CSV data, it is sometimes desirable to simply ignore
diff --git a/src/reader.rs b/src/reader.rs
@@ -1330,7 +1330,7 @@ impl<R: io::Read> Reader<R> {
         match headers.string_record {
             Ok(ref record) => Ok(record),
             Err(ref err) => Err(Error::new(ErrorKind::Utf8 {
-                pos: headers.byte_record.position().map(Clone::clone),
+                pos: headers.byte_record.position().cloned(),
                 err: err.clone(),
             })),
         }
@@ -1888,7 +1888,7 @@ impl ReaderState {
                 Some(expected) => {
                     if record.len() as u64 != expected {
                         return Err(Error::new(ErrorKind::UnequalLengths {
-                            pos: record.position().map(Clone::clone),
+                            pos: record.position().cloned(),
                             expected_len: expected,
                             len: record.len() as u64,
                         }));
@@ -1916,7 +1916,7 @@ impl<R: io::Read, D: DeserializeOwned> DeserializeRecordsIntoIter<R, D> {
         let headers = if !rdr.state.has_headers {
             None
         } else {
-            rdr.headers().ok().map(Clone::clone)
+            rdr.headers().ok().cloned()
         };
         DeserializeRecordsIntoIter {
             rdr,
@@ -1974,7 +1974,7 @@ impl<'r, R: io::Read, D: DeserializeOwned> DeserializeRecordsIter<'r, R, D> {
         let headers = if !rdr.state.has_headers {
             None
         } else {
-            rdr.headers().ok().map(Clone::clone)
+            rdr.headers().ok().cloned()
         };
         DeserializeRecordsIter {
             rdr,
@@ -1986,12 +1986,12 @@ impl<'r, R: io::Read, D: DeserializeOwned> DeserializeRecordsIter<'r, R, D> {
 
     /// Return a reference to the underlying CSV reader.
     pub fn reader(&self) -> &Reader<R> {
-        &self.rdr
+        self.rdr
     }
 
     /// Return a mutable reference to the underlying CSV reader.
     pub fn reader_mut(&mut self) -> &mut Reader<R> {
-        &mut self.rdr
+        self.rdr
     }
 }
 
@@ -2064,12 +2064,12 @@ impl<'r, R: io::Read> StringRecordsIter<'r, R> {
 
     /// Return a reference to the underlying CSV reader.
     pub fn reader(&self) -> &Reader<R> {
-        &self.rdr
+        self.rdr
     }
 
     /// Return a mutable reference to the underlying CSV reader.
     pub fn reader_mut(&mut self) -> &mut Reader<R> {
-        &mut self.rdr
+        self.rdr
     }
 }
 
@@ -2140,12 +2140,12 @@ impl<'r, R: io::Read> ByteRecordsIter<'r, R> {
 
     /// Return a reference to the underlying CSV reader.
     pub fn reader(&self) -> &Reader<R> {
-        &self.rdr
+        self.rdr
     }
 
     /// Return a mutable reference to the underlying CSV reader.
     pub fn reader_mut(&mut self) -> &mut Reader<R> {
-        &mut self.rdr
+        self.rdr
     }
 }
 
diff --git a/src/serializer.rs b/src/serializer.rs
diff --git a/src/string_record.rs b/src/string_record.rs

Original file line number	Diff line number	Diff line change
`@@ -698,7 +698,7 @@ impl Bounds {`
`698`	`698`	/// If there are no fields, this returns `0`.
`699`	`699`	`#[inline]`
`700`	`700`	`fn end(&self) -> usize {`
`701`		`- self.ends().last().map(\|&i\| i).unwrap_or(0)`
	`701`	`+ self.ends().last().copied().unwrap_or(0)`
`702`	`702`	`}`
`703`	`703`
`704`	`704`	`/// Returns the number of fields in these bounds.`