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 {

components/script/dom/htmlscriptelement.rs

@@ -898,15 +898,15 @@ impl HTMLScriptElement {
             warn!("Error creating input and output files for unminify");
         }
 
-        let path;
-        match window_from_node(self).unminified_js_dir() {
-            Some(unminified_js_dir) => path = PathBuf::from(unminified_js_dir),
+        let path = match window_from_node(self).unminified_js_dir() {
+            Some(unminified_js_dir) => PathBuf::from(unminified_js_dir),
             None => {
                 warn!("Unminified script directory not found");
                 return;
             },
-        }
-        let (base, has_name) = match script.url.as_str().ends_with("/") {
+        };
+
+        let (base, has_name) = match script.url.as_str().ends_with('/') {
             true => (
                 path.join(&script.url[url::Position::BeforeHost..])
                     .as_path()

components/script/dom/htmlselectelement.rs

@@ -518,11 +518,10 @@ impl Validatable for HTMLSelectElement {
         // https://html.spec.whatwg.org/multipage/#the-select-element%3Asuffering-from-being-missing
         if validate_flags.contains(ValidationFlags::VALUE_MISSING) && self.Required() {
             let placeholder = self.get_placeholder_label_option();
-            let selected_option = self
+            let is_value_missing = !self
                 .list_of_options()
-                .filter(|e| e.Selected() && placeholder.as_ref() != Some(e))
-                .next();
-            failed_flags.set(ValidationFlags::VALUE_MISSING, selected_option.is_none());
+                .any(|e| e.Selected() && placeholder != Some(e));
+            failed_flags.set(ValidationFlags::VALUE_MISSING, is_value_missing);
         }
 
         failed_flags

components/script/dom/htmlvideoelement.rs

@@ -279,12 +279,9 @@ impl VirtualMethods for HTMLVideoElement {
         self.super_type().unwrap().attribute_mutated(attr, mutation);
 
         if let Some(new_value) = mutation.new_value(attr) {
-            match attr.local_name() {
-                &local_name!("poster") => {
-                    self.fetch_poster_frame(&new_value);
-                },
-                _ => (),
-            };
+            if attr.local_name() == &local_name!("poster") {
+                self.fetch_poster_frame(&new_value);
+            }
         }
     }
 }

components/script/dom/navigator.rs

@@ -82,10 +82,8 @@ impl Navigator {
     }
 
     pub fn gamepads(&self) -> DomRoot<GamepadList> {
-        let gamepads = self
-            .gamepads
-            .or_init(|| GamepadList::new(&self.global(), &[]));
-        gamepads
+        self.gamepads
+            .or_init(|| GamepadList::new(&self.global(), &[]))
     }
 
     pub fn has_gamepad_gesture(&self) -> bool {

components/script/dom/node.rs

@@ -10,7 +10,7 @@ use std::default::Default;
 use std::ops::Range;
 use std::slice::from_ref;
 use std::sync::Arc as StdArc;
-use std::{cmp, iter, mem};
+use std::{cmp, iter};
 
 use app_units::Au;
 use bitflags::bitflags;
@@ -454,7 +454,7 @@ pub struct QuerySelectorIterator {
     iterator: TreeIterator,
 }
 
-impl<'a> QuerySelectorIterator {
+impl QuerySelectorIterator {
     fn new(iter: TreeIterator, selectors: SelectorList<SelectorImpl>) -> QuerySelectorIterator {
         QuerySelectorIterator {
             selectors,
@@ -463,7 +463,7 @@ impl<'a> QuerySelectorIterator {
     }
 }
 
-impl<'a> Iterator for QuerySelectorIterator {
+impl Iterator for QuerySelectorIterator {
     type Item = DomRoot<Node>;
 
     fn next(&mut self) -> Option<DomRoot<Node>> {
@@ -1203,8 +1203,7 @@ impl Node {
                 match last_child.and_then(|node| {
                     node.inclusively_preceding_siblings()
                         .filter_map(DomRoot::downcast::<Element>)
-                        .filter(|elem| is_delete_type(elem))
-                        .next()
+                        .find(|elem| is_delete_type(elem))
                 }) {
                     Some(element) => element,
                     None => return Ok(()),
@@ -1314,10 +1313,10 @@ where
 #[allow(unsafe_code)]
 pub unsafe fn from_untrusted_node_address(candidate: UntrustedNodeAddress) -> DomRoot<Node> {
     // https://github.com/servo/servo/issues/6383
-    let candidate: uintptr_t = mem::transmute(candidate.0);
+    let candidate = candidate.0 as usize;
     //        let object: *mut JSObject = jsfriendapi::bindgen::JS_GetAddressableObject(runtime,
     //                                                                                  candidate);
-    let object: *mut JSObject = mem::transmute(candidate);
+    let object = candidate as *mut JSObject;
     if object.is_null() {
         panic!("Attempted to create a `Dom<Node>` from an invalid pointer!")
     }