diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index 50b598c86e5..9e55648f5eb 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -877,8 +877,10 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
                 let key = self.webrender_api.generate_font_instance_key();
                 let mut transaction = Transaction::new();
 
-                let mut font_instance_options = FontInstanceOptions::default();
-                font_instance_options.flags = flags;
+                let font_instance_options = FontInstanceOptions {
+                    flags,
+                    ..Default::default()
+                };
                 transaction.add_font_instance(
                     key,
                     font_key,
diff --git a/components/gfx/font.rs b/components/gfx/font.rs
index de42f6c321c..fe899a4ea82 100644
--- a/components/gfx/font.rs
+++ b/components/gfx/font.rs
@@ -443,7 +443,7 @@ impl FontGroup {
             .font_family
             .families
             .iter()
-            .map(|family| FontGroupFamily::new(family))
+            .map(FontGroupFamily::new)
             .collect();
 
         FontGroup {
@@ -465,10 +465,8 @@ impl FontGroup {
         let should_look_for_small_caps = self.descriptor.variant == font_variant_caps::T::SmallCaps &&
             codepoint.is_ascii_lowercase();
         let font_or_synthesized_small_caps = |font: FontRef| {
-            if should_look_for_small_caps {
-                if font.synthesized_small_caps.is_some() {
-                    return font.synthesized_small_caps.clone();
-                }
+            if should_look_for_small_caps && font.synthesized_small_caps.is_some() {
+                return font.synthesized_small_caps.clone();
             }
             Some(font)
         };
@@ -565,7 +563,6 @@ impl FontGroup {
             .chain(fallback_font_families(codepoint).into_iter().map(|family| {
                 FontFamilyDescriptor::new(FontFamilyName::from(family), FontSearchScope::Local)
             }))
-            .into_iter()
             .filter_map(|family_descriptor| {
                 FontGroupFamily {
                     family_descriptor,
@@ -646,11 +643,11 @@ impl FontGroupFamily {
             .next()
     }
 
-    fn members<'a, S: FontSource>(
-        &'a mut self,
+    fn members<S: FontSource>(
+        &mut self,
         font_descriptor: &FontDescriptor,
         font_context: &FontContext<S>,
-    ) -> impl Iterator<Item = &mut FontGroupFamilyMember> + 'a {
+    ) -> impl Iterator<Item = &mut FontGroupFamilyMember> {
         let family_descriptor = &self.family_descriptor;
         let members = self.members.get_or_insert_with(|| {
             font_context
diff --git a/components/gfx/font_cache_thread.rs b/components/gfx/font_cache_thread.rs
index 3c1790edb6f..22cd5edee47 100644
--- a/components/gfx/font_cache_thread.rs
+++ b/components/gfx/font_cache_thread.rs
@@ -108,7 +108,7 @@ impl FontTemplates {
         // If a request is made for a font family that exists,
         // pick the first valid font in the family if we failed
         // to find an exact match for the descriptor.
-        for template in &mut self.templates.iter() {
+        if let Some(template) = self.templates.first() {
             return vec![template.clone()];
         }
 
@@ -231,7 +231,7 @@ impl FontCache {
                             .font_data
                             .entry(identifier)
                             .or_insert_with(|| font_template.data());
-                        let _ = bytes_sender.send(&data);
+                        let _ = bytes_sender.send(data);
                     }
                 },
                 Command::GetFontInstance(identifier, pt_size, flags, result) => {
@@ -557,10 +557,7 @@ impl From<&FontFaceRuleData> for CSSFontFaceDescriptors {
                 ),
             }
         }
-        let style = rule_data
-            .style
-            .as_ref()
-            .map(|style| style_to_computed(style));
+        let style = rule_data.style.as_ref().map(style_to_computed);
         let unicode_range = rule_data
             .unicode_range
             .as_ref()
diff --git a/components/gfx/platform/freetype/font.rs b/components/gfx/platform/freetype/font.rs
index f68e370e6d3..c6c7f802c3b 100644
--- a/components/gfx/platform/freetype/font.rs
+++ b/components/gfx/platform/freetype/font.rs
@@ -338,7 +338,7 @@ impl PlatformFontMethods for PlatformFont {
     }
 }
 
-impl<'a> PlatformFont {
+impl PlatformFont {
     fn set_char_size(face: FT_Face, pt_size: Au) -> Result<(), &'static str> {
         let char_size = pt_size.to_f64_px() * 64.0 + 0.5;
 
diff --git a/components/gfx/platform/freetype/font_list.rs b/components/gfx/platform/freetype/font_list.rs
index 65a6457b25d..a958248f8c5 100644
--- a/components/gfx/platform/freetype/font_list.rs
+++ b/components/gfx/platform/freetype/font_list.rs
@@ -268,9 +268,9 @@ fn font_weight_from_fontconfig_pattern(pattern: *mut FcPattern) -> Option<FontWe
 
     let mapping = [
         (0., 0.),
-        (FC_WEIGHT_REGULAR as f64, 400 as f64),
-        (FC_WEIGHT_BOLD as f64, 700 as f64),
-        (FC_WEIGHT_EXTRABLACK as f64, 1000 as f64),
+        (FC_WEIGHT_REGULAR as f64, 400_f64),
+        (FC_WEIGHT_BOLD as f64, 700_f64),
+        (FC_WEIGHT_EXTRABLACK as f64, 1000_f64),
     ];
 
     let mapped_weight = map_platform_values_to_style_values(&mapping, weight as f64);
diff --git a/components/script/dom/abstractworkerglobalscope.rs b/components/script/dom/abstractworkerglobalscope.rs
index 835438c5f23..50844953a21 100644
--- a/components/script/dom/abstractworkerglobalscope.rs
+++ b/components/script/dom/abstractworkerglobalscope.rs
@@ -91,9 +91,9 @@ pub trait WorkerEventLoopMethods {
     fn task_queue(&self) -> &TaskQueue<Self::WorkerMsg>;
     fn handle_event(&self, event: Self::Event) -> bool;
     fn handle_worker_post_event(&self, worker: &TrustedWorkerAddress) -> Option<AutoWorkerReset>;
-    fn from_control_msg(&self, msg: Self::ControlMsg) -> Self::Event;
-    fn from_worker_msg(&self, msg: Self::WorkerMsg) -> Self::Event;
-    fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> Self::Event;
+    fn from_control_msg(msg: Self::ControlMsg) -> Self::Event;
+    fn from_worker_msg(msg: Self::WorkerMsg) -> Self::Event;
+    fn from_devtools_msg(msg: DevtoolScriptControlMsg) -> Self::Event;
     fn control_receiver(&self) -> &Receiver<Self::ControlMsg>;
 }
 
@@ -114,13 +114,13 @@ pub fn run_worker_event_loop<T, WorkerMsg, Event>(
         .map(|_| scope.from_devtools_receiver());
     let task_queue = worker_scope.task_queue();
     let event = select! {
-        recv(worker_scope.control_receiver()) -> msg => worker_scope.from_control_msg(msg.unwrap()),
+        recv(worker_scope.control_receiver()) -> msg => T::from_control_msg(msg.unwrap()),
         recv(task_queue.select()) -> msg => {
             task_queue.take_tasks(msg.unwrap());
-            worker_scope.from_worker_msg(task_queue.recv().unwrap())
+            T::from_worker_msg(task_queue.recv().unwrap())
         },
         recv(devtools_port.unwrap_or(&crossbeam_channel::never())) -> msg =>
-            worker_scope.from_devtools_msg(msg.unwrap()),
+            T::from_devtools_msg(msg.unwrap()),
     };
     let mut sequential = vec![];
     sequential.push(event);
@@ -136,9 +136,9 @@ pub fn run_worker_event_loop<T, WorkerMsg, Event>(
             Err(_) => match devtools_port.map(|port| port.try_recv()) {
                 None => {},
                 Some(Err(_)) => break,
-                Some(Ok(ev)) => sequential.push(worker_scope.from_devtools_msg(ev)),
+                Some(Ok(ev)) => sequential.push(T::from_devtools_msg(ev)),
             },
-            Ok(ev) => sequential.push(worker_scope.from_worker_msg(ev)),
+            Ok(ev) => sequential.push(T::from_worker_msg(ev)),
         }
     }
     // Step 3
diff --git a/components/script/dom/bindings/record.rs b/components/script/dom/bindings/record.rs
index 33377b0dd09..c437b8955f7 100644
--- a/components/script/dom/bindings/record.rs
+++ b/components/script/dom/bindings/record.rs
@@ -195,3 +195,9 @@ where
         rval.set(ObjectValue(js_object.handle().get()));
     }
 }
+
+impl<K: RecordKey, V> Default for Record<K, V> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/components/script/dom/bluetooth.rs b/components/script/dom/bluetooth.rs
index 77ca187a671..7ae54893064 100644
--- a/components/script/dom/bluetooth.rs
+++ b/components/script/dom/bluetooth.rs
@@ -98,6 +98,12 @@ impl BluetoothExtraPermissionData {
     }
 }
 
+impl Default for BluetoothExtraPermissionData {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 struct BluetoothContext<T: AsyncBluetoothListener + DomObject> {
     promise: Option<TrustedPromise>,
     receiver: Trusted<T>,
diff --git a/components/script/dom/dedicatedworkerglobalscope.rs b/components/script/dom/dedicatedworkerglobalscope.rs
index 7e1c9e1abc3..b8647c305ce 100644
--- a/components/script/dom/dedicatedworkerglobalscope.rs
+++ b/components/script/dom/dedicatedworkerglobalscope.rs
@@ -219,15 +219,15 @@ impl WorkerEventLoopMethods for DedicatedWorkerGlobalScope {
         Some(ar)
     }
 
-    fn from_control_msg(&self, msg: DedicatedWorkerControlMsg) -> MixedMessage {
+    fn from_control_msg(msg: DedicatedWorkerControlMsg) -> MixedMessage {
         MixedMessage::Control(msg)
     }
 
-    fn from_worker_msg(&self, msg: DedicatedWorkerScriptMsg) -> MixedMessage {
+    fn from_worker_msg(msg: DedicatedWorkerScriptMsg) -> MixedMessage {
         MixedMessage::Worker(msg)
     }
 
-    fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> MixedMessage {
+    fn from_devtools_msg(msg: DevtoolScriptControlMsg) -> MixedMessage {
         MixedMessage::Devtools(msg)
     }
 
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 85e1d53e95d..c67780115ef 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -994,8 +994,8 @@ impl Document {
                 // (like Acid2).
                 let device_pixel_ratio = self.window.device_pixel_ratio().get();
                 (
-                    rect.origin.x.to_nearest_pixel(device_pixel_ratio) as f32,
-                    rect.origin.y.to_nearest_pixel(device_pixel_ratio) as f32,
+                    rect.origin.x.to_nearest_pixel(device_pixel_ratio),
+                    rect.origin.y.to_nearest_pixel(device_pixel_ratio),
                 )
             })
             .or_else(|| {
diff --git a/components/script/dom/elementinternals.rs b/components/script/dom/elementinternals.rs
index 716bddd94b0..3956b1cccc8 100644
--- a/components/script/dom/elementinternals.rs
+++ b/components/script/dom/elementinternals.rs
@@ -238,7 +238,7 @@ impl ElementInternalsMethods for ElementInternals {
         if bits.is_empty() {
             self.set_validation_message(DOMString::new());
         } else {
-            self.set_validation_message(message.unwrap_or_else(DOMString::new));
+            self.set_validation_message(message.unwrap_or_default());
         }
 
         // Step 6: If element's customError validity flag is true, then set element's custom validity error
diff --git a/components/script/dom/identityhub.rs b/components/script/dom/identityhub.rs
index 1fe8051f44c..976637dac51 100644
--- a/components/script/dom/identityhub.rs
+++ b/components/script/dom/identityhub.rs
@@ -218,3 +218,9 @@ impl Identities {
         self.select(id.backend()).render_bundles.free(id);
     }
 }
+
+impl Default for Identities {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index b3b7fca3904..19178806944 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -1325,7 +1325,7 @@ pub trait LayoutNodeHelpers<'dom> {
     fn owner_doc_for_layout(self) -> LayoutDom<'dom, Document>;
     fn containing_shadow_root_for_layout(self) -> Option<LayoutDom<'dom, ShadowRoot>>;
 
-    fn is_element_for_layout(self) -> bool;
+    fn is_element_for_layout(&self) -> bool;
     unsafe fn get_flag(self, flag: NodeFlags) -> bool;
     unsafe fn set_flag(self, flag: NodeFlags, value: bool);
 
@@ -1387,8 +1387,8 @@ impl<'dom> LayoutNodeHelpers<'dom> for LayoutDom<'dom, Node> {
     }
 
     #[inline]
-    fn is_element_for_layout(self) -> bool {
-        self.is::<Element>()
+    fn is_element_for_layout(&self) -> bool {
+        (*self).is::<Element>()
     }
 
     #[inline]
diff --git a/components/script/dom/offlineaudiocontext.rs b/components/script/dom/offlineaudiocontext.rs
index 072f19d80da..fcdffddb449 100644
--- a/components/script/dom/offlineaudiocontext.rs
+++ b/components/script/dom/offlineaudiocontext.rs
@@ -81,8 +81,7 @@ impl OfflineAudioContext {
         if channel_count > MAX_CHANNEL_COUNT ||
             channel_count == 0 ||
             length == 0 ||
-            sample_rate < MIN_SAMPLE_RATE ||
-            sample_rate > MAX_SAMPLE_RATE
+            !(MIN_SAMPLE_RATE..=MAX_SAMPLE_RATE).contains(&sample_rate)
         {
             return Err(Error::NotSupported);
         }
diff --git a/components/script/dom/serviceworkerglobalscope.rs b/components/script/dom/serviceworkerglobalscope.rs
index 36b2ccd9504..8bede70297e 100644
--- a/components/script/dom/serviceworkerglobalscope.rs
+++ b/components/script/dom/serviceworkerglobalscope.rs
@@ -201,15 +201,15 @@ impl WorkerEventLoopMethods for ServiceWorkerGlobalScope {
         None
     }
 
-    fn from_control_msg(&self, msg: ServiceWorkerControlMsg) -> MixedMessage {
+    fn from_control_msg(msg: ServiceWorkerControlMsg) -> MixedMessage {
         MixedMessage::Control(msg)
     }
 
-    fn from_worker_msg(&self, msg: ServiceWorkerScriptMsg) -> MixedMessage {
+    fn from_worker_msg(msg: ServiceWorkerScriptMsg) -> MixedMessage {
         MixedMessage::ServiceWorker(msg)
     }
 
-    fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> MixedMessage {
+    fn from_devtools_msg(msg: DevtoolScriptControlMsg) -> MixedMessage {
         MixedMessage::Devtools(msg)
     }
 
diff --git a/components/script/dom/servoparser/async_html.rs b/components/script/dom/servoparser/async_html.rs
index 95081d753eb..7200b9ed5c6 100644
--- a/components/script/dom/servoparser/async_html.rs
+++ b/components/script/dom/servoparser/async_html.rs
@@ -283,7 +283,6 @@ impl Tokenizer {
         tokenizer
     }
 
-    #[must_use]
     pub fn feed(&mut self, input: &mut BufferQueue) -> TokenizerResult<DomRoot<HTMLScriptElement>> {
         let mut send_tendrils = VecDeque::new();
         while let Some(str) = input.pop_front() {
diff --git a/components/script/dom/servoparser/html.rs b/components/script/dom/servoparser/html.rs
index 11b26869963..ade1fdf4613 100644
--- a/components/script/dom/servoparser/html.rs
+++ b/components/script/dom/servoparser/html.rs
@@ -78,7 +78,6 @@ impl Tokenizer {
         Tokenizer { inner }
     }
 
-    #[must_use]
     pub fn feed(&mut self, input: &mut BufferQueue) -> TokenizerResult<DomRoot<HTMLScriptElement>> {
         match self.inner.feed(input) {
             TokenizerResult::Done => TokenizerResult::Done,
diff --git a/components/script/dom/servoparser/mod.rs b/components/script/dom/servoparser/mod.rs
index 3d8fbc347b4..507e2a2cb99 100644
--- a/components/script/dom/servoparser/mod.rs
+++ b/components/script/dom/servoparser/mod.rs
@@ -698,7 +698,6 @@ enum Tokenizer {
 }
 
 impl Tokenizer {
-    #[must_use]
     fn feed(&mut self, input: &mut BufferQueue) -> TokenizerResult<DomRoot<HTMLScriptElement>> {
         match *self {
             Tokenizer::Html(ref mut tokenizer) => tokenizer.feed(input),
diff --git a/components/script/dom/servoparser/xml.rs b/components/script/dom/servoparser/xml.rs
index d07d6bc6afb..26b43910100 100644
--- a/components/script/dom/servoparser/xml.rs
+++ b/components/script/dom/servoparser/xml.rs
@@ -41,7 +41,6 @@ impl Tokenizer {
         Tokenizer { inner: tok }
     }
 
-    #[must_use]
     pub fn feed(&mut self, input: &mut BufferQueue) -> TokenizerResult<DomRoot<HTMLScriptElement>> {
         self.inner.run(input);
         match self.inner.sink.sink.script.take() {