Fix all clippy warnings (#564)

* Fix all clippy warnings

* Revert usage of inclusive ranges

* Remove redundant function argument

* Revert use of unavailable pointer methods

* Introduce ContiguousCaseRange

lib/codegen/src/ir/dfg.rs

@@ -127,7 +127,7 @@ fn maybe_resolve_aliases(values: &PrimaryMap<Value, ValueData>, value: Value) ->
     let mut v = value;
 
     // Note that values may be empty here.
-    for _ in 0..1 + values.len() {
+    for _ in 0..values.len() + 1 {
         if let ValueData::Alias { original, .. } = values[v] {
             v = original;
         } else {
@@ -174,8 +174,7 @@ impl<'a> Iterator for Values<'a> {
     fn next(&mut self) -> Option<Self::Item> {
         self.inner
             .by_ref()
-            .filter(|kv| valid_valuedata(kv.1))
-            .next()
+            .find(|kv| valid_valuedata(kv.1))
             .map(|kv| kv.0)
     }
 }

lib/codegen/src/ir/function.rs

@@ -178,19 +178,14 @@ impl Function {
     ///
     /// This function can only be used after the code layout has been computed by the
     /// `binemit::relax_branches()` function.
-    pub fn inst_offsets<'a>(
-        &'a self,
-        func: &'a Function,
-        ebb: Ebb,
-        encinfo: &EncInfo,
-    ) -> InstOffsetIter<'a> {
+    pub fn inst_offsets<'a>(&'a self, ebb: Ebb, encinfo: &EncInfo) -> InstOffsetIter<'a> {
         assert!(
             !self.offsets.is_empty(),
             "Code layout must be computed first"
         );
         InstOffsetIter {
             encinfo: encinfo.clone(),
-            func,
+            func: self,
             divert: RegDiversions::new(),
             encodings: &self.encodings,
             offset: self.offsets[ebb],