lint: resolve a few Clippy warnings

These changes only reflect a subset that I agreed with.

PR #135

src/dfa.rs

@@ -494,7 +494,7 @@ impl Builder {
             matches: vec![vec![]; num_match_states],
             matches_memory_usage: 0,
             pattern_lens: nnfa.pattern_lens_raw().to_vec(),
-            prefilter: nnfa.prefilter().map(|p| p.clone()),
+            prefilter: nnfa.prefilter().cloned(),
             match_kind: nnfa.match_kind(),
             state_len,
             alphabet_len: byte_classes.alphabet_len(),

src/nfa/contiguous.rs

@@ -821,7 +821,7 @@ impl<'a> State<'a> {
 
     /// Return an iterator over every explicitly defined transition in this
     /// state.
-    fn transitions<'b>(&'b self) -> impl Iterator<Item = (u8, StateID)> + 'b {
+    fn transitions(&self) -> impl Iterator<Item = (u8, StateID)> + '_ {
         let mut i = 0;
         core::iter::from_fn(move || match self.trans {
             StateTrans::Sparse { classes, nexts } => {

src/packed/api.rs

@@ -676,7 +676,7 @@ impl<'s, 'h> Iterator for FindIter<'s, 'h> {
         if self.span.start > self.span.end {
             return None;
         }
-        match self.searcher.find_in(&self.haystack, self.span) {
+        match self.searcher.find_in(self.haystack, self.span) {
             None => None,
             Some(m) => {
                 self.span.start = m.end();

src/packed/pattern.rs

@@ -211,7 +211,7 @@ pub(crate) struct Pattern<'a>(&'a [u8]);
 impl<'a> fmt::Debug for Pattern<'a> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Pattern")
-            .field("lit", &String::from_utf8_lossy(&self.0))
+            .field("lit", &String::from_utf8_lossy(self.0))
             .finish()
     }
 }
@@ -224,7 +224,7 @@ impl<'p> Pattern<'p> {
 
     /// Returns the bytes of this pattern.
     pub(crate) fn bytes(&self) -> &[u8] {
-        &self.0
+        self.0
     }
 
     /// Returns the first `len` low nybbles from this pattern. If this pattern

src/util/prefilter.rs

@@ -330,7 +330,7 @@ struct Packed(packed::Searcher);
 impl PrefilterI for Packed {
     fn find_in(&self, haystack: &[u8], span: Span) -> Candidate {
         self.0
-            .find_in(&haystack, span)
+            .find_in(haystack, span)
             .map_or(Candidate::None, Candidate::Match)
     }
 }
@@ -549,7 +549,7 @@ impl RareBytesBuilder {
             let (mut bytes, mut len) = ([0; 3], 0);
             for b in 0..=255 {
                 if builder.rare_set.contains(b) {
-                    bytes[len] = b as u8;
+                    bytes[len] = b;
                     len += 1;
                 }
             }
@@ -604,7 +604,7 @@ impl RareBytesBuilder {
             self.available = false;
             return;
         }
-        let mut rarest = match bytes.get(0) {
+        let mut rarest = match bytes.first() {
             None => return,
             Some(&b) => (b, freq_rank(b)),
         };
@@ -835,7 +835,7 @@ impl StartBytesBuilder {
         if self.count > 3 {
             return;
         }
-        if let Some(&byte) = bytes.get(0) {
+        if let Some(&byte) = bytes.first() {
             self.add_one_byte(byte);
             if self.ascii_case_insensitive {
                 self.add_one_byte(opposite_ascii_case(byte));