*: Fix clippy warnings

src/encoding.rs

@@ -299,7 +299,6 @@ enum LabelValueEncoderInner<'a> {
 
 impl<'a> LabelValueEncoder<'a> {
     /// Finish encoding the label value.
-    #[must_use]
     pub fn finish(self) -> Result<(), std::fmt::Error> {
         for_both!(self, LabelValueEncoderInner, e, e.finish())
     }
@@ -394,13 +393,13 @@ impl<'a> EncodeLabelValue for Cow<'a, str> {
     }
 }
 
-impl<'a> EncodeLabelValue for f64 {
+impl EncodeLabelValue for f64 {
     fn encode(&self, encoder: &mut LabelValueEncoder) -> Result<(), std::fmt::Error> {
         encoder.write_str(dtoa::Buffer::new().format(*self))
     }
 }
 
-impl<'a> EncodeLabelValue for u64 {
+impl EncodeLabelValue for u64 {
     fn encode(&self, encoder: &mut LabelValueEncoder) -> Result<(), std::fmt::Error> {
         encoder.write_str(itoa::Buffer::new().format(*self))
     }

src/encoding/text.rs

@@ -209,7 +209,7 @@ impl<'a, 'b> MetricEncoder<'a, 'b> {
         self.newline()?;
 
         let mut cummulative = 0;
-        for (i, (upper_bound, count)) in buckets.into_iter().enumerate() {
+        for (i, (upper_bound, count)) in buckets.iter().enumerate() {
             cummulative += count;
 
             self.write_name_and_unit()?;

src/registry.rs

@@ -54,25 +54,14 @@ use std::borrow::Cow;
 /// #                "# EOF\n";
 /// # assert_eq!(expected, buffer);
 /// ```
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct Registry {
     prefix: Option<Prefix>,
     labels: Vec<(Cow<'static, str>, Cow<'static, str>)>,
     metrics: Vec<(Descriptor, Box<dyn Metric>)>,
     sub_registries: Vec<Registry>,
 }
 
-impl Default for Registry {
-    fn default() -> Self {
-        Self {
-            prefix: None,
-            labels: Default::default(),
-            metrics: Default::default(),
-            sub_registries: vec![],
-        }
-    }
-}
-
 impl Registry {
     /// Creates a new default [`Registry`] with the given prefix.
     pub fn with_prefix(prefix: impl Into<String>) -> Self {