clippy: Fix a variety of warnings in components/script/dom (#31894)

components/script/dom/bindings/root.rs

@@ -76,8 +76,16 @@ where
     }
 }
 
-/// Represents values that can be rooted through a stable address that will
+/// `StableTraceObject` represents values that can be rooted through a stable address that will
 /// not change for their whole lifetime.
+/// It is an unsafe trait that requires implementors to ensure certain safety guarantees.
+///
+/// # Safety
+///
+/// Implementors of this trait must ensure that the `trace` method correctly accounts for all
+/// owned and referenced objects, so that the garbage collector can accurately determine which
+/// objects are still in use. Failing to adhere to this contract may result in undefined behavior,
+/// such as use-after-free errors.
 pub unsafe trait StableTraceObject {
     /// Returns a stable trace object which address won't change for the whole
     /// lifetime of the value.
@@ -267,10 +275,7 @@ impl RootCollection {
     unsafe fn unroot(&self, object: *const dyn JSTraceable) {
         assert_in_script();
         let roots = &mut *self.roots.get();
-        match roots
-            .iter()
-            .rposition(|r| *r as *const () == object as *const ())
-        {
+        match roots.iter().rposition(|r| std::ptr::eq(*r, object)) {
             Some(idx) => {
                 roots.remove(idx);
             },
@@ -486,7 +491,7 @@ impl<T> Eq for Dom<T> {}
 
 impl<T> PartialEq for LayoutDom<'_, T> {
     fn eq(&self, other: &Self) -> bool {
-        self.value as *const T == other.value as *const T
+        std::ptr::eq(self.value, other.value)
     }
 }
 

components/script/dom/bindings/str.rs

@@ -40,6 +40,11 @@ impl ByteString {
         self.0.len()
     }
 
+    /// Checks if the ByteString is empty.
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
     /// Returns `self` with A–Z replaced by a–z.
     pub fn to_lower(&self) -> ByteString {
         ByteString::new(self.0.to_ascii_lowercase())
@@ -365,7 +370,7 @@ impl DOMString {
         let (year_int, month_int) = parse_month_component(value)?;
 
         // Step 4
-        if value.split("-").nth(2).is_some() {
+        if value.split('-').nth(2).is_some() {
             return None;
         }
         // Step 5
@@ -443,7 +448,7 @@ impl DOMString {
             if !(
                 // A valid number is the same as what rust considers to be valid,
                 // except for +1., NaN, and Infinity.
-                val.is_infinite() || val.is_nan() || input.ends_with(".") || input.starts_with('+')
+                val.is_infinite() || val.is_nan() || input.ends_with('.') || input.starts_with('+')
             ) {
                 return Some(val);
             }
@@ -677,7 +682,7 @@ fn parse_month_component(value: &str) -> Option<(i32, u32)> {
 
     // Step 4, 5
     let month_int = month.parse::<u32>().ok()?;
-    if month.len() != 2 || month_int > 12 || month_int < 1 {
+    if month.len() != 2 || !(1..=12).contains(&month_int) {
         return None;
     }
 

components/script/dom/bindings/structuredclone.rs

@@ -169,12 +169,14 @@ unsafe extern "C" fn read_transfer_callback(
         let sc_holder = &mut *(closure as *mut StructuredDataHolder);
         let in_realm_proof = AlreadyInRealm::assert_for_cx(SafeJSContext::from_ptr(cx));
         let owner = GlobalScope::from_context(cx, InRealm::Already(&in_realm_proof));
-        if let Ok(_) = <MessagePort as Transferable>::transfer_receive(
+        if <MessagePort as Transferable>::transfer_receive(
             &owner,
             sc_holder,
             extra_data,
             return_object,
-        ) {
+        )
+        .is_ok()
+        {
             return true;
         }
     }

components/script/dom/bindings/utils.rs

@@ -197,7 +197,7 @@ pub unsafe fn get_array_index_from_id(_cx: *mut JSContext, id: HandleId) -> Opti
     let first_char = char::decode_utf16(chars.iter().cloned())
         .next()
         .map_or('\0', |r| r.unwrap_or('\0'));
-    if first_char < 'a' || first_char > 'z' {
+    if !('a'..='z').contains(&first_char) {
         return None;
     }
 

components/script/dom/bindings/xmlname.rs

@@ -90,8 +90,7 @@ pub enum XMLName {
 /// for details.
 pub fn xml_name_type(name: &str) -> XMLName {
     fn is_valid_start(c: char) -> bool {
-        match c {
-            ':' |
+        matches!(c, ':' |
             'A'..='Z' |
             '_' |
             'a'..='z' |
@@ -106,9 +105,7 @@ pub fn xml_name_type(name: &str) -> XMLName {
             '\u{3001}'..='\u{D7FF}' |
             '\u{F900}'..='\u{FDCF}' |
             '\u{FDF0}'..='\u{FFFD}' |
-            '\u{10000}'..='\u{EFFFF}' => true,
-            _ => false,
-        }
+            '\u{10000}'..='\u{EFFFF}')
     }
 
     fn is_valid_continuation(c: char) -> bool {