refactor: improve code coverage a little bit

crates/oxc_allocator/src/arena.rs

@@ -145,11 +145,12 @@ impl<'alloc, T> ops::Index<usize> for &'alloc Vec<'alloc, T> {
     }
 }
 
-impl<'alloc, T> ops::IndexMut<usize> for Vec<'alloc, T> {
-    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
-        self.0.index_mut(index)
-    }
-}
+// Unused right now.
+// impl<'alloc, T> ops::IndexMut<usize> for Vec<'alloc, T> {
+// fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+// self.0.index_mut(index)
+// }
+// }
 
 impl<'alloc, T> Serialize for Vec<'alloc, T>
 where

crates/oxc_macros/src/declare_oxc_lint.rs

@@ -6,20 +6,6 @@ use syn::{
     Attribute, Error, Ident, Lit, LitStr, Meta, Result, Token,
 };
 
-fn parse_attr<const LEN: usize>(path: [&'static str; LEN], attr: &Attribute) -> Option<LitStr> {
-    if let Meta::NameValue(name_value) = attr.parse_meta().ok()? {
-        let path_idents = name_value.path.segments.iter().map(|segment| &segment.ident);
-
-        if itertools::equal(path_idents, path) {
-            if let Lit::Str(lit) = name_value.lit {
-                return Some(lit);
-            }
-        }
-    }
-
-    None
-}
-
 pub struct LintRuleMeta {
     name: Ident,
     category: Ident,
@@ -90,3 +76,16 @@ pub fn declare_oxc_lint(metadata: LintRuleMeta) -> TokenStream {
 
     output
 }
+
+fn parse_attr<const LEN: usize>(path: [&'static str; LEN], attr: &Attribute) -> Option<LitStr> {
+    if let Meta::NameValue(name_value) = attr.parse_meta().ok()? {
+        let path_idents = name_value.path.segments.iter().map(|segment| &segment.ident);
+
+        if itertools::equal(path_idents, path) {
+            if let Lit::Str(lit) = name_value.lit {
+                return Some(lit);
+            }
+        }
+    }
+    unreachable!()
+}

crates/oxc_parser/src/js/function.rs

@@ -16,14 +16,14 @@ type ArrowFunctionHead<'a> = (
     Span,
 );
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Clone, Copy)]
 pub enum IsParenthesizedArrowFunction {
     True,
     False,
     Maybe,
 }
 
-#[derive(PartialEq, Eq, Debug, Copy, Clone)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub enum FunctionKind {
     Declaration { single_statement: bool },
     Expression,

crates/oxc_parser/src/lexer/token.rs

@@ -5,7 +5,7 @@ use oxc_span::Span;
 
 use super::kind::Kind;
 
-#[derive(Debug, Clone, PartialEq, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct Token<'a> {
     /// Token Kind
     pub kind: Kind,
@@ -38,7 +38,7 @@ impl<'a> Token<'a> {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone)]
 pub enum TokenValue<'a> {
     None,
     Number(f64),
@@ -47,7 +47,7 @@ pub enum TokenValue<'a> {
     RegExp(RegExp<'a>),
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone)]
 pub struct RegExp<'a> {
     pub pattern: &'a str,
     pub flags: RegExpFlags,
@@ -63,21 +63,21 @@ impl<'a> TokenValue<'a> {
     pub fn as_number(&self) -> f64 {
         match self {
             Self::Number(s) => *s,
-            _ => panic!("expected number!"),
+            _ => unreachable!("expected number!"),
         }
     }
 
     pub fn as_bigint(&self) -> num_bigint::BigInt {
         match self {
             Self::BigInt(s) => s.clone(),
-            _ => panic!("expected bigint!"),
+            _ => unreachable!("expected bigint!"),
         }
     }
 
     pub fn as_regex(&self) -> &RegExp<'a> {
         match self {
             Self::RegExp(regex) => regex,
-            _ => panic!("expected regex!"),
+            _ => unreachable!("expected regex!"),
         }
     }
 

crates/oxc_parser/src/ts/statement.rs

@@ -30,7 +30,7 @@ impl<'a> Parser<'a> {
         span: Span,
         modifiers: Modifiers<'a>,
     ) -> Result<Declaration<'a>> {
-        self.expect(Kind::Enum)?;
+        self.bump_any(); // bump `enum`
 
         let id = self.parse_binding_identifier()?;
         let members = TSEnumMemberList::parse(self)?.members;

crates/oxc_resolver/src/cache.rs

@@ -27,7 +27,7 @@ struct IdentityHasher(u64);
 
 impl Hasher for IdentityHasher {
     fn write(&mut self, _: &[u8]) {
-        panic!("Invalid use of IdentityHasher")
+        unreachable!("Invalid use of IdentityHasher")
     }
     fn write_u64(&mut self, n: u64) {
         self.0 = n;

crates/oxc_syntax/src/scope.rs

@@ -8,7 +8,7 @@ define_index_type! {
 }
 
 bitflags! {
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    #[derive(Debug, Clone, Copy)]
     pub struct ScopeFlags: u16 {
         const StrictMode       = 1 << 0;
         const Top              = 1 << 1;

crates/oxc_syntax/src/symbol.rs

@@ -8,7 +8,7 @@ define_index_type! {
 }
 
 bitflags! {
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+    #[derive(Debug, Clone, Copy)]
     pub struct SymbolFlags: u32 {
         const None                    = 0;
         /// Variable (var) or parameter