fix: Make clippy happy

Author: Swatinem

src/lib.rs

@@ -2231,15 +2231,15 @@ impl<'a> Serializer<'a> {
             Name::Operator(ref op) => {
                 match *op {
                     Operator::Ctor => {
-                        let prev = names.scope.names.iter().next().ok_or_else(|| {
+                        let prev = names.scope.names.get(0).ok_or_else(|| {
                             Error::new(
                                 "If there's a ctor, there should be another name in this sequence",
                             )
                         })?;
                         self.write_one_name(prev)?;
                     }
                     Operator::Dtor => {
-                        let prev = names.scope.names.iter().next().ok_or_else(|| {
+                        let prev = names.scope.names.get(0).ok_or_else(|| {
                             Error::new(
                                 "If there's a dtor, there should be another name in this sequence",
                             )

tests/test_llvm.rs

@@ -29,8 +29,8 @@ fn parse_cases<'a, I: Iterator<Item = &'a str>>(i: I) -> impl Iterator<Item = Te
             Some(LineRule::CheckNotInvalid)
         } else if item.starts_with("; CHECK-NOT: ") {
             panic!("unsupported rule: {}", &item[2..]);
-        } else if item.starts_with("; CHECK: ") {
-            Some(LineRule::Check(&item[9..]))
+        } else if let Some(item) = item.strip_prefix("; CHECK: ") {
+            Some(LineRule::Check(item))
         } else if item.starts_with(';') {
             None
         } else {
@@ -45,7 +45,9 @@ fn parse_cases<'a, I: Iterator<Item = &'a str>>(i: I) -> impl Iterator<Item = Te
             Some(LineRule::CheckNotInvalid) => {
                 not_invalid = true;
             }
-            Some(LineRule::Input(input)) => {
+            Some(LineRule::Input(input)) =>
+            {
+                #[allow(clippy::while_let_on_iterator)]
                 while let Some(next) = rule_iter.next() {
                     match next {
                         LineRule::CheckNotInvalid => {