clippy: fix warnings in various modules in components (#31568)

* clippy: fix warnings in various modules in components

* fix: unit tests

* fix: build on android

* fix: all samplers use new_boxed

components/allocator/lib.rs

@@ -13,9 +13,7 @@ pub use crate::platform::*;
 mod platform {
     use std::os::raw::c_void;
 
-    use jemallocator;
-
-    pub use self::jemallocator::Jemalloc as Allocator;
+    pub use jemallocator::Jemalloc as Allocator;
 
     /// Get the size of a heap block.
     pub unsafe extern "C" fn usable_size(ptr: *const c_void) -> usize {

components/background_hang_monitor/background_hang_monitor.rs

@@ -92,19 +92,19 @@ impl BackgroundHangMonitorRegister for HangMonitorRegister {
             target_os = "windows",
             any(target_arch = "x86_64", target_arch = "x86")
         ))]
-        let sampler = crate::sampler_windows::WindowsSampler::new();
+        let sampler = crate::sampler_windows::WindowsSampler::new_boxed();
         #[cfg(target_os = "macos")]
-        let sampler = crate::sampler_mac::MacOsSampler::new();
+        let sampler = crate::sampler_mac::MacOsSampler::new_boxed();
         #[cfg(all(
             target_os = "linux",
             not(any(target_arch = "arm", target_arch = "aarch64"))
         ))]
-        let sampler = crate::sampler_linux::LinuxSampler::new();
+        let sampler = crate::sampler_linux::LinuxSampler::new_boxed();
         #[cfg(any(
             target_os = "android",
             all(target_os = "linux", any(target_arch = "arm", target_arch = "aarch64"))
         ))]
-        let sampler = crate::sampler::DummySampler::new();
+        let sampler = crate::sampler::DummySampler::new_boxed();
 
         // When a component is registered, and there's an exit request that
         // reached BHM, we want an exit signal to be delivered to the
@@ -208,7 +208,7 @@ impl BackgroundHangMonitorChan {
         BackgroundHangMonitorChan {
             sender,
             _tether: tether,
-            component_id: component_id,
+            component_id,
             disconnected: Default::default(),
             monitoring_enabled,
         }
@@ -312,14 +312,14 @@ struct BackgroundHangMonitorWorker {
     monitoring_enabled: bool,
 }
 
+type MonitoredComponentSender = Sender<(MonitoredComponentId, MonitoredComponentMsg)>;
+type MonitoredComponentReceiver = Receiver<(MonitoredComponentId, MonitoredComponentMsg)>;
+
 impl BackgroundHangMonitorWorker {
     fn new(
         constellation_chan: IpcSender<HangMonitorAlert>,
         control_port: IpcReceiver<BackgroundHangMonitorControlMsg>,
-        (port_sender, port): (
-            Arc<Sender<(MonitoredComponentId, MonitoredComponentMsg)>>,
-            Receiver<(MonitoredComponentId, MonitoredComponentMsg)>,
-        ),
+        (port_sender, port): (Arc<MonitoredComponentSender>, MonitoredComponentReceiver),
         tether_port: Receiver<Never>,
         monitoring_enabled: bool,
     ) -> Self {
@@ -360,7 +360,7 @@ impl BackgroundHangMonitorWorker {
             let profile = stack.to_hangprofile();
             let name = match self.component_names.get(&id) {
                 Some(ref s) => format!("\"{}\"", s),
-                None => format!("null"),
+                None => "null".to_string(),
             };
             let json = format!(
                 "{}{{ \"name\": {}, \"namespace\": {}, \"index\": {}, \"type\": \"{:?}\", \
@@ -389,12 +389,10 @@ impl BackgroundHangMonitorWorker {
                 .checked_sub(Instant::now() - self.last_sample)
                 .unwrap_or_else(|| Duration::from_millis(0));
             after(duration)
+        } else if self.monitoring_enabled {
+            after(Duration::from_millis(100))
         } else {
-            if self.monitoring_enabled {
-                after(Duration::from_millis(100))
-            } else {
-                never()
-            }
+            never()
         };
 
         let received = select! {
@@ -403,13 +401,8 @@ impl BackgroundHangMonitorWorker {
                 // gets disconnected.
                 Some(event.unwrap())
             },
-            recv(self.tether_port) -> event => {
+            recv(self.tether_port) -> _ => {
                 // This arm can only reached by a tether disconnection
-                match event {
-                    Ok(x) => match x {}
-                    Err(_) => {}
-                }
-
                 // All associated `HangMonitorRegister` and
                 // `BackgroundHangMonitorChan` have been dropped. Suppress
                 // `signal_to_exit` and exit the BHM.

components/background_hang_monitor/sampler.rs

@@ -4,7 +4,6 @@
 
 use std::ptr;
 
-use backtrace;
 use msg::constellation_msg::{HangProfile, HangProfileSymbol};
 
 const MAX_NATIVE_FRAMES: usize = 1024;
@@ -18,7 +17,7 @@ pub struct DummySampler;
 
 impl DummySampler {
     #[allow(dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         Box::new(DummySampler)
     }
 }
@@ -64,12 +63,12 @@ impl NativeStack {
         instruction_ptr: *mut std::ffi::c_void,
         stack_ptr: *mut std::ffi::c_void,
     ) -> Result<(), ()> {
-        if !(self.count < MAX_NATIVE_FRAMES) {
+        if self.count >= MAX_NATIVE_FRAMES {
             return Err(());
         }
         self.instruction_ptrs[self.count] = instruction_ptr;
         self.stack_ptrs[self.count] = stack_ptr;
-        self.count = self.count + 1;
+        self.count += 1;
         Ok(())
     }
 
@@ -85,7 +84,7 @@ impl NativeStack {
                 // TODO: use the demangled or C++ demangled symbols if available.
                 let name = symbol
                     .name()
-                    .map(|n| String::from_utf8_lossy(&n.as_bytes()).to_string());
+                    .map(|n| String::from_utf8_lossy(n.as_bytes()).to_string());
                 let filename = symbol.filename().map(|n| n.to_string_lossy().to_string());
                 let lineno = symbol.lineno();
                 profile.backtrace.push(HangProfileSymbol {

components/background_hang_monitor/sampler_linux.rs

@@ -6,9 +6,8 @@
 
 use std::cell::UnsafeCell;
 use std::sync::atomic::{AtomicPtr, Ordering};
-use std::{io, mem, process, ptr, thread};
+use std::{cmp, io, mem, process, ptr, thread};
 
-use libc;
 use nix::sys::signal::{sigaction, SaFlags, SigAction, SigHandler, SigSet, Signal};
 use unwind_sys::{
     unw_cursor_t, unw_get_reg, unw_init_local, unw_step, UNW_ESUCCESS, UNW_REG_IP, UNW_REG_SP,
@@ -138,7 +137,7 @@ pub struct LinuxSampler {
 
 impl LinuxSampler {
     #[allow(unsafe_code, dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = unsafe { libc::syscall(libc::SYS_gettid) as libc::pid_t };
         let handler = SigHandler::SigAction(sigprof_handler);
         let action = SigAction::new(
@@ -181,12 +180,10 @@ fn step(cursor: *mut unw_cursor_t) -> Result<bool, i32> {
         }
 
         let ret = unw_step(cursor);
-        if ret > 0 {
-            Ok(true)
-        } else if ret == 0 {
-            Ok(false)
-        } else {
-            Err(ret)
+        match ret.cmp(&0) {
+            cmp::Ordering::Less => Err(ret),
+            cmp::Ordering::Greater => Ok(true),
+            cmp::Ordering::Equal => Ok(false),
         }
     }
 }
@@ -222,6 +219,7 @@ impl Sampler for LinuxSampler {
             let ret = unsafe { unw_init_local(cursor.as_mut_ptr(), context) };
             result = if ret == UNW_ESUCCESS {
                 let mut native_stack = NativeStack::new();
+                #[allow(clippy::while_let_loop)] // False positive
                 loop {
                     let ip = match get_register(cursor.as_mut_ptr(), RegNum::Ip) {
                         Ok(ip) => ip,

components/background_hang_monitor/sampler_mac.rs

@@ -16,7 +16,7 @@ pub struct MacOsSampler {
 
 impl MacOsSampler {
     #[allow(unsafe_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = unsafe { mach2::mach_init::mach_thread_self() };
         Box::new(MacOsSampler { thread_id })
     }

components/background_hang_monitor/sampler_windows.rs

@@ -13,7 +13,7 @@ pub struct WindowsSampler {
 
 impl WindowsSampler {
     #[allow(unsafe_code, dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = 0; // TODO: use winapi::um::processthreadsapi::GetThreadId
         Box::new(WindowsSampler { thread_id })
     }

components/dom_struct/lib.rs

@@ -20,13 +20,13 @@ pub fn dom_struct(args: TokenStream, input: TokenStream) -> TokenStream {
     // Work around https://github.com/rust-lang/rust/issues/46489
     let attributes: TokenStream = attributes.to_string().parse().unwrap();
 
-    let output: TokenStream = attributes.into_iter().chain(input.into_iter()).collect();
+    let output: TokenStream = attributes.into_iter().chain(input).collect();
 
     let item: Item = syn::parse(output).unwrap();
 
     if let Item::Struct(s) = item {
         let s2 = s.clone();
-        if s.generics.params.len() > 0 {
+        if !s.generics.params.is_empty() {
             return quote!(#s2).into();
         }
         if let Fields::Named(ref f) = s.fields {

components/domobject_derive/lib.rs

@@ -4,7 +4,6 @@
 
 #![recursion_limit = "128"]
 
-use proc_macro2;
 use quote::{quote, TokenStreamExt};
 use syn::parse_quote;
 

components/hyper_serde/lib.rs

@@ -531,7 +531,7 @@ impl<'a> Serialize for Ser<'a, Mime> {
     where
         S: Serializer,
     {
-        serializer.serialize_str(&self.v.as_ref())
+        serializer.serialize_str(self.v.as_ref())
     }
 }
 

components/layout/display_list/builder.rs

@@ -80,7 +80,7 @@ static THREAD_TINT_COLORS: [ColorF; 8] = [
         a: 0.7,
     },
     ColorF {
-        r: 255.0 / 255.0,
+        r: 1.0,
         g: 212.0 / 255.0,
         b: 83.0 / 255.0,
         a: 0.7,
@@ -110,7 +110,7 @@ static THREAD_TINT_COLORS: [ColorF; 8] = [
         a: 0.7,
     },
     ColorF {
-        r: 255.0 / 255.0,
+        r: 1.0,
         g: 249.0 / 255.0,
         b: 201.0 / 255.0,
         a: 0.7,

components/layout/parallel.rs

@@ -29,16 +29,23 @@ const CHUNK_SIZE: usize = 16;
 pub type FlowList = SmallVec<[UnsafeFlow; CHUNK_SIZE]>;
 
 /// Vtable + pointer representation of a Flow trait object.
-#[derive(Clone, Copy, Eq, PartialEq)]
+#[derive(Clone, Copy, Eq)]
 pub struct UnsafeFlow(*const dyn Flow);
 
 unsafe impl Sync for UnsafeFlow {}
 unsafe impl Send for UnsafeFlow {}
+impl PartialEq for UnsafeFlow {
+    fn eq(&self, other: &Self) -> bool {
+        // Compare the pointers explicitly to avoid clippy lint
+        self.0 as *const u8 == other.0 as *const u8
+    }
+}
 
 fn null_unsafe_flow() -> UnsafeFlow {
     UnsafeFlow(ptr::null::<BlockFlow>())
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)] // It has an unsafe block inside
 pub fn mut_owned_flow_to_unsafe_flow(flow: *mut FlowRef) -> UnsafeFlow {
     unsafe { UnsafeFlow(&**flow) }
 }

components/media/lib.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 #![deny(unsafe_code)]
+#![allow(clippy::type_complexity)]
 
 mod media_channel;
 mod media_thread;

components/media/media_channel/mod.rs

@@ -74,6 +74,7 @@ where
         }
     }
 
+    #[allow(clippy::wrong_self_convention)] // It is an alias to the underlying module
     pub fn to_opaque(self) -> ipc_channel::ipc::OpaqueIpcReceiver {
         match self {
             GLPlayerReceiver::Ipc(receiver) => receiver.to_opaque(),

components/media/media_thread.rs

@@ -79,14 +79,14 @@ impl GLPlayerThread {
                 }
             },
             GLPlayerMsg::Lock(id, handler_sender) => {
-                self.players.get(&id).map(|sender| {
+                if let Some(sender) = self.players.get(&id) {
                     sender.send(GLPlayerMsgForward::Lock(handler_sender)).ok();
-                });
+                }
             },
             GLPlayerMsg::Unlock(id) => {
-                self.players.get(&id).map(|sender| {
+                if let Some(sender) = self.players.get(&id) {
                     sender.send(GLPlayerMsgForward::Unlock()).ok();
-                });
+                }
             },
             GLPlayerMsg::Exit => return true,
         }

components/pixels/lib.rs

@@ -49,9 +49,7 @@ pub fn rgba8_get_rect(pixels: &[u8], size: Size2D<u64>, rect: Rect<u64>) -> Cow<
 pub fn rgba8_byte_swap_colors_inplace(pixels: &mut [u8]) {
     assert!(pixels.len() % 4 == 0);
     for rgba in pixels.chunks_mut(4) {
-        let b = rgba[0];
-        rgba[0] = rgba[2];
-        rgba[2] = b;
+        rgba.swap(0, 2);
     }
 }
 
@@ -79,7 +77,7 @@ pub fn rgba8_premultiply_inplace(pixels: &mut [u8]) -> bool {
 }
 
 pub fn multiply_u8_color(a: u8, b: u8) -> u8 {
-    return (a as u32 * b as u32 / 255) as u8;
+    (a as u32 * b as u32 / 255) as u8
 }
 
 pub fn clip(

components/profile/mem.rs

@@ -30,8 +30,8 @@ pub struct Profiler {
     created: Instant,
 }
 
-const JEMALLOC_HEAP_ALLOCATED_STR: &'static str = "jemalloc-heap-allocated";
-const SYSTEM_HEAP_ALLOCATED_STR: &'static str = "system-heap-allocated";
+const JEMALLOC_HEAP_ALLOCATED_STR: &str = "jemalloc-heap-allocated";
+const SYSTEM_HEAP_ALLOCATED_STR: &str = "system-heap-allocated";
 
 impl Profiler {
     pub fn create(period: Option<f64>) -> ProfilerChan {
@@ -84,7 +84,7 @@ impl Profiler {
 
     pub fn new(port: IpcReceiver<ProfilerMsg>) -> Profiler {
         Profiler {
-            port: port,
+            port,
             reporters: HashMap::new(),
             created: Instant::now(),
         }
@@ -212,7 +212,7 @@ impl Profiler {
 
         println!("|");
         println!("End memory reports");
-        println!("");
+        println!();
     }
 }
 
@@ -239,7 +239,7 @@ impl ReportsTree {
         ReportsTree {
             size: 0,
             count: 0,
-            path_seg: path_seg,
+            path_seg,
             children: vec![],
         }
     }
@@ -259,7 +259,7 @@ impl ReportsTree {
     fn insert(&mut self, path: &[String], size: usize) {
         let mut t: &mut ReportsTree = self;
         for path_seg in path {
-            let i = match t.find_child(&path_seg) {
+            let i = match t.find_child(path_seg) {
                 Some(i) => i,
                 None => {
                     let new_t = ReportsTree::new(path_seg.clone());
@@ -352,7 +352,7 @@ impl ReportsForest {
 
     fn print(&mut self) {
         // Fill in sizes of interior nodes, and recursively sort the sub-trees.
-        for (_, tree) in &mut self.trees {
+        for tree in self.trees.values_mut() {
             tree.compute_interior_node_sizes_and_sort();
         }
 
@@ -360,7 +360,7 @@ impl ReportsForest {
         // single node) come after non-degenerate trees. Secondary sort: alphabetical order of the
         // root node's path_seg.
         let mut v = vec![];
-        for (_, tree) in &self.trees {
+        for tree in self.trees.values() {
             v.push(tree);
         }
         v.sort_by(|a, b| {
@@ -412,9 +412,9 @@ mod system_reporter {
             let mut report = |path, size| {
                 if let Some(size) = size {
                     reports.push(Report {
-                        path: path,
+                        path,
                         kind: ReportKind::NonExplicitSize,
-                        size: size,
+                        size,
                     });
                 }
             };
@@ -663,7 +663,7 @@ mod system_reporter {
 
                 // Construct the segment name from its pathname and permissions.
                 curr_seg_name.clear();
-                if pathname == "" || pathname.starts_with("[stack:") {
+                if pathname.is_empty() || pathname.starts_with("[stack:") {
                     // Anonymous memory. Entries marked with "[stack:nnn]"
                     // look like thread stacks but they may include other
                     // anonymous mappings, so we can't trust them and just
@@ -674,7 +674,7 @@ mod system_reporter {
                 }
                 curr_seg_name.push_str(" (");
                 curr_seg_name.push_str(perms);
-                curr_seg_name.push_str(")");
+                curr_seg_name.push(')');
 
                 looking_for = LookingFor::Rss;
             } else {

components/profile/time.rs

@@ -184,9 +184,9 @@ impl Profiler {
                     })
                     .expect("Thread spawning failed");
                 // decide if we need to spawn the timer thread
-                match option {
-                    &OutputOptions::FileName(_) => { /* no timer thread needed */ },
-                    &OutputOptions::Stdout(period) => {
+                match *option {
+                    OutputOptions::FileName(_) => { /* no timer thread needed */ },
+                    OutputOptions::Stdout(period) => {
                         // Spawn a timer thread
                         let chan = chan.clone();
                         thread::Builder::new()
@@ -241,11 +241,11 @@ impl Profiler {
         output: Option<OutputOptions>,
     ) -> Profiler {
         Profiler {
-            port: port,
+            port,
             buckets: BTreeMap::new(),
-            output: output,
+            output,
             last_msg: None,
-            trace: trace,
+            trace,
             blocked_layout_queries: HashMap::new(),
         }
     }
@@ -259,7 +259,7 @@ impl Profiler {
     }
 
     fn find_or_insert(&mut self, k: (ProfilerCategory, Option<TimerMetadata>), t: f64) {
-        self.buckets.entry(k).or_insert_with(Vec::new).push(t);
+        self.buckets.entry(k).or_default().push(t);
     }
 
     fn handle_msg(&mut self, msg: ProfilerMsg) -> bool {
@@ -321,24 +321,24 @@ impl Profiler {
         match self.output {
             Some(OutputOptions::FileName(ref filename)) => {
                 let path = Path::new(&filename);
-                let mut file = match File::create(&path) {
+                let mut file = match File::create(path) {
                     Err(e) => panic!("Couldn't create {}: {}", path.display(), e),
                     Ok(file) => file,
                 };
-                write!(
+                writeln!(
                     file,
                     "_category_\t_incremental?_\t_iframe?_\t_url_\t_mean (ms)_\t\
-                     _median (ms)_\t_min (ms)_\t_max (ms)_\t_events_\n"
+                     _median (ms)_\t_min (ms)_\t_max (ms)_\t_events_"
                 )
                 .unwrap();
-                for (&(ref category, ref meta), ref mut data) in &mut self.buckets {
+                for ((category, meta), ref mut data) in &mut self.buckets {
                     data.sort_by(|a, b| a.partial_cmp(b).expect("No NaN values in profiles"));
                     let data_len = data.len();
                     if data_len > 0 {
                         let (mean, median, min, max) = Self::get_statistics(data);
-                        write!(
+                        writeln!(
                             file,
-                            "{}\t{}\t{:15.4}\t{:15.4}\t{:15.4}\t{:15.4}\t{:15}\n",
+                            "{}\t{}\t{:15.4}\t{:15.4}\t{:15.4}\t{:15.4}\t{:15}",
                             category.format(&self.output),
                             meta.format(&self.output),
                             mean,
@@ -351,9 +351,9 @@ impl Profiler {
                     }
                 }
 
-                write!(file, "_url\t_blocked layout queries_\n").unwrap();
+                writeln!(file, "_url\t_blocked layout queries_").unwrap();
                 for (url, count) in &self.blocked_layout_queries {
-                    write!(file, "{}\t{}\n", url, count).unwrap();
+                    writeln!(file, "{}\t{}", url, count).unwrap();
                 }
             },
             Some(OutputOptions::Stdout(_)) => {
@@ -374,7 +374,7 @@ impl Profiler {
                     "      _events_"
                 )
                 .unwrap();
-                for (&(ref category, ref meta), ref mut data) in &mut self.buckets {
+                for ((category, meta), ref mut data) in &mut self.buckets {
                     data.sort_by(|a, b| a.partial_cmp(b).expect("No NaN values in profiles"));
                     let data_len = data.len();
                     if data_len > 0 {
@@ -393,13 +393,13 @@ impl Profiler {
                         .unwrap();
                     }
                 }
-                writeln!(&mut lock, "").unwrap();
+                writeln!(&mut lock).unwrap();
 
                 writeln!(&mut lock, "_url_\t_blocked layout queries_").unwrap();
                 for (url, count) in &self.blocked_layout_queries {
                     writeln!(&mut lock, "{}\t{}", url, count).unwrap();
                 }
-                writeln!(&mut lock, "").unwrap();
+                writeln!(&mut lock).unwrap();
             },
             None => { /* Do nothing if no output option has been set */ },
         };

components/profile/trace_dump.rs

@@ -37,7 +37,7 @@ impl TraceDump {
     {
         let mut file = fs::File::create(trace_file_path)?;
         write_prologue(&mut file)?;
-        Ok(TraceDump { file: file })
+        Ok(TraceDump { file })
     }
 
     /// Write one trace to the trace dump file.

components/range/lib.rs

@@ -204,10 +204,7 @@ impl<I: RangeIndex> Range<I> {
     /// ~~~
     #[inline]
     pub fn new(begin: I, length: I) -> Range<I> {
-        Range {
-            begin: begin,
-            length: length,
-        }
+        Range { begin, length }
     }
 
     #[inline]

components/remutex/lib.rs

@@ -36,7 +36,7 @@ impl ThreadId {
         ThreadId(NonZeroUsize::new(number).unwrap())
     }
     pub fn current() -> ThreadId {
-        THREAD_ID.with(|tls| tls.clone())
+        THREAD_ID.with(|tls| *tls)
     }
 }
 
@@ -46,10 +46,13 @@ thread_local! { static THREAD_ID: ThreadId = ThreadId::new() }
 #[derive(Debug)]
 pub struct AtomicOptThreadId(AtomicUsize);
 
-impl AtomicOptThreadId {
-    pub fn new() -> AtomicOptThreadId {
+impl Default for AtomicOptThreadId {
+    fn default() -> Self {
         AtomicOptThreadId(AtomicUsize::new(0))
     }
+}
+
+impl AtomicOptThreadId {
     pub fn store(&self, value: Option<ThreadId>, ordering: Ordering) {
         let number = value.map(|id| id.0.get()).unwrap_or(0);
         self.0.store(number, ordering);
@@ -75,14 +78,17 @@ pub struct HandOverHandMutex {
     guard: UnsafeCell<Option<MutexGuard<'static, ()>>>,
 }
 
-impl HandOverHandMutex {
-    pub fn new() -> HandOverHandMutex {
-        HandOverHandMutex {
+impl Default for HandOverHandMutex {
+    fn default() -> Self {
+        Self {
             mutex: Mutex::new(()),
-            owner: AtomicOptThreadId::new(),
+            owner: AtomicOptThreadId::default(),
             guard: UnsafeCell::new(None),
         }
     }
+}
+
+impl HandOverHandMutex {
     #[allow(unsafe_code)]
     unsafe fn set_guard_and_owner<'a>(&'a self, guard: MutexGuard<'a, ()>) {
         // The following two lines allow us to unsafely store
@@ -107,7 +113,7 @@ impl HandOverHandMutex {
         assert_eq!(old_owner, Some(ThreadId::current()));
     }
     #[allow(unsafe_code)]
-    pub fn lock<'a>(&'a self) -> LockResult<()> {
+    pub fn lock(&self) -> LockResult<()> {
         let (guard, result) = match self.mutex.lock() {
             Ok(guard) => (guard, Ok(())),
             Err(err) => (err.into_inner(), Err(PoisonError::new(()))),
@@ -163,9 +169,9 @@ impl<T> ReentrantMutex<T> {
     pub fn new(data: T) -> ReentrantMutex<T> {
         trace!("{:?} Creating new lock.", ThreadId::current());
         ReentrantMutex {
-            mutex: HandOverHandMutex::new(),
+            mutex: HandOverHandMutex::default(),
             count: Cell::new(0),
-            data: data,
+            data,
         }
     }
 
@@ -173,7 +179,7 @@ impl<T> ReentrantMutex<T> {
         trace!("{:?} Locking.", ThreadId::current());
         if self.mutex.owner() != Some(ThreadId::current()) {
             trace!("{:?} Becoming owner.", ThreadId::current());
-            if let Err(_) = self.mutex.lock() {
+            if self.mutex.lock().is_err() {
                 trace!("{:?} Poison!", ThreadId::current());
                 return Err(PoisonError::new(self.mk_guard()));
             }

components/script/build.rs

@@ -31,16 +31,16 @@ fn main() {
     println!("Binding generation completed in {:?}", start.elapsed());
 
     let json = out_dir.join("InterfaceObjectMapData.json");
-    let json: Value = serde_json::from_reader(File::open(&json).unwrap()).unwrap();
+    let json: Value = serde_json::from_reader(File::open(json).unwrap()).unwrap();
     let mut map = phf_codegen::Map::new();
     for (key, value) in json.as_object().unwrap() {
         map.entry(Bytes(key), value.as_str().unwrap());
     }
     let phf = PathBuf::from(env::var_os("OUT_DIR").unwrap()).join("InterfaceObjectMapPhf.rs");
-    let mut phf = File::create(&phf).unwrap();
-    write!(
+    let mut phf = File::create(phf).unwrap();
+    writeln!(
         &mut phf,
-        "pub static MAP: phf::Map<&'static [u8], fn(JSContext, HandleObject)> = {};\n",
+        "pub static MAP: phf::Map<&'static [u8], fn(JSContext, HandleObject)> = {};",
         map.build(),
     )
     .unwrap();

components/servo/lib.rs

@@ -387,7 +387,7 @@ where
             embedder.register_webxr(&mut webxr_main_thread, embedder_proxy.clone());
         }
 
-        let wgpu_image_handler = webgpu::WGPUExternalImages::new();
+        let wgpu_image_handler = webgpu::WGPUExternalImages::default();
         let wgpu_image_map = wgpu_image_handler.images.clone();
         external_image_handlers.set_handler(
             Box::new(wgpu_image_handler),

components/url/lib.rs

@@ -176,7 +176,7 @@ impl ServoUrl {
                 // Strip `scheme://`, which is hardly useful for identifying websites
                 let mut st = self.as_str();
                 st = st.strip_prefix(self.scheme()).unwrap_or(st);
-                st = st.strip_prefix(":").unwrap_or(st);
+                st = st.strip_prefix(':').unwrap_or(st);
                 st = st.trim_start_matches('/');
 
                 // Don't want to return an empty string

components/webgpu/lib.rs

@@ -919,8 +919,8 @@ impl<'a> WGPU<'a> {
                         pipeline_id,
                     } => {
                         let desc = DeviceDescriptor {
-                            label: descriptor.label.as_ref().map(|l| crate::Cow::from(l)),
-                            features: descriptor.features.clone(),
+                            label: descriptor.label.as_ref().map(crate::Cow::from),
+                            features: descriptor.features,
                             limits: descriptor.limits.clone(),
                         };
                         let global = &self.global;
@@ -1336,20 +1336,12 @@ webgpu_resource!(WebGPUSurface, id::SurfaceId);
 webgpu_resource!(WebGPUTexture, id::TextureId);
 webgpu_resource!(WebGPUTextureView, id::TextureViewId);
 
+#[derive(Default)]
 pub struct WGPUExternalImages {
     pub images: Arc<Mutex<HashMap<u64, PresentationData>>>,
     pub locked_ids: HashMap<u64, Vec<u8>>,
 }
 
-impl WGPUExternalImages {
-    pub fn new() -> Self {
-        Self {
-            images: Arc::new(Mutex::new(HashMap::new())),
-            locked_ids: HashMap::new(),
-        }
-    }
-}
-
 impl WebrenderExternalImageApi for WGPUExternalImages {
     fn lock(&mut self, id: u64) -> (WebrenderImageSource, Size2D<i32>) {
         let size;