Fix a bunch of clippy lints

58 files changed, 280 insertions, 355 deletions

diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index f4c67e49269..ce4e379ba4e 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -512,14 +512,12 @@ impl<Window: WindowMethods> IOCompositor<Window> {
 
             (Msg::ScrollTimeout(timestamp), ShutdownState::NotShuttingDown) => {
                 debug!("scroll timeout, drawing unpainted content!");
-                match self.composition_request {
-                    CompositionRequest::CompositeOnScrollTimeout(this_timestamp) => {
-                        if timestamp == this_timestamp {
-                            self.composition_request = CompositionRequest::CompositeNow(
-                                CompositingReason::HitScrollTimeout)
-                        }
+                if let CompositionRequest::CompositeOnScrollTimeout(this_timestamp) =
+                    self.composition_request {
+                    if timestamp == this_timestamp {
+                        self.composition_request = CompositionRequest::CompositeNow(
+                            CompositingReason::HitScrollTimeout)
                     }
-                    _ => {}
                 }
             }
 
@@ -644,7 +642,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         if !self.pipeline_details.contains_key(&pipeline_id) {
             self.pipeline_details.insert(pipeline_id, PipelineDetails::new());
         }
-        return self.pipeline_details.get_mut(&pipeline_id).unwrap();
+        self.pipeline_details.get_mut(&pipeline_id).unwrap()
     }
 
     pub fn pipeline(&self, pipeline_id: PipelineId) -> Option<&CompositionPipeline> {
@@ -730,7 +728,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             root_layer.bounds.borrow_mut().size = Size2D::from_untyped(&frame_size);
         }
 
-        return root_layer;
+        root_layer
     }
 
     fn create_pipeline_details_for_frame_tree(&mut self, frame_tree: &SendableFrameTree) {
@@ -1223,11 +1221,8 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             result.layer.send_event(self, TouchEvent(TouchEventType::Up, identifier,
                                                      result.point.to_untyped()));
         }
-        match self.touch_handler.on_touch_up(identifier, point) {
-            TouchAction::Click => {
-                self.simulate_mouse_click(point);
-            }
-            _ => {}
+        if let TouchAction::Click = self.touch_handler.on_touch_up(identifier, point) {
+            self.simulate_mouse_click(point);
         }
     }
 
@@ -1882,7 +1877,7 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             return None;
         }
 
-        return Some(HitTestResult { layer: layer, point: point_in_parent_layer });
+        Some(HitTestResult { layer: layer, point: point_in_parent_layer })
     }
 
     fn find_topmost_layer_at_point(&self,
@@ -2001,7 +1996,7 @@ fn find_layer_with_pipeline_and_layer_id_for_layer(layer: Rc<Layer<CompositorDat
         }
     }
 
-    return None;
+    None
 }
 
 impl<Window> CompositorEventListener for IOCompositor<Window> where Window: WindowMethods {
diff --git a/components/compositing/compositor_layer.rs b/components/compositing/compositor_layer.rs
index 157b98a68d4..d5fd0cb04c9 100644
--- a/components/compositing/compositor_layer.rs
+++ b/components/compositing/compositor_layer.rs
@@ -359,9 +359,9 @@ impl CompositorLayer for Layer<CompositorData> {
         }
 
         if result {
-            return ScrollEventResult::ScrollPositionChanged;
+            ScrollEventResult::ScrollPositionChanged
         } else {
-            return ScrollEventResult::ScrollPositionUnchanged;
+            ScrollEventResult::ScrollPositionUnchanged
         }
     }
 
@@ -414,7 +414,7 @@ impl CompositorLayer for Layer<CompositorData> {
             result |= child.scroll_layer_and_all_child_layers(offset_for_children);
         }
 
-        return result;
+        result
     }
 
     fn wants_scroll_events(&self) -> WantsScrollEventsFlag {
diff --git a/components/compositing/timer_scheduler.rs b/components/compositing/timer_scheduler.rs
index b81290bc74d..528dc17821d 100644
--- a/components/compositing/timer_scheduler.rs
+++ b/components/compositing/timer_scheduler.rs
@@ -155,14 +155,14 @@ impl TimerScheduler {
 
             let ret = sel.wait();
             if ret == scheduler_handle.id() {
-                port.recv().ok().map(|req| Task::HandleRequest(req))
+                port.recv().ok().map(Task::HandleRequest)
             } else if ret == timer_handle.id() {
                 timer_port.recv().ok().map(|_| Task::DispatchDueEvents)
             } else {
                 panic!("unexpected select result!")
             }
         } else {
-            port.recv().ok().map(|req| Task::HandleRequest(req))
+            port.recv().ok().map(Task::HandleRequest)
         }
     }
 
@@ -172,8 +172,7 @@ impl TimerScheduler {
         let schedule_for = precise_time_ns() + duration_ns;
 
         let previously_earliest = self.scheduled_events.borrow().peek()
-                .map(|scheduled| scheduled.for_time)
-                .unwrap_or(Length::new(u64::max_value()));
+                .map_or(Length::new(u64::max_value()), |scheduled| scheduled.for_time);
 
         self.scheduled_events.borrow_mut().push(ScheduledEvent {
             request: request,
diff --git a/components/compositing/touch.rs b/components/compositing/touch.rs
index 1dbd9914f89..4f20afedd63 100644
--- a/components/compositing/touch.rs
+++ b/components/compositing/touch.rs
@@ -203,16 +203,15 @@ impl TouchHandler {
     }
 
     pub fn on_event_processed(&mut self, result: EventResult) {
-        match self.state {
-            WaitingForScript => self.state = match result {
+        if let WaitingForScript = self.state {
+            self.state = match result {
                 EventResult::DefaultPrevented => DefaultPrevented,
                 EventResult::DefaultAllowed => match self.touch_count() {
                     1 => Touching,
                     2 => Pinching,
                     _ => MultiTouch,
                 }
-            },
-            _ => {}
+            }
         }
     }
 
diff --git a/components/devtools/actors/network_event.rs b/components/devtools/actors/network_event.rs
index eb77f174a9d..dc70eb4b215 100644
--- a/components/devtools/actors/network_event.rs
+++ b/components/devtools/actors/network_event.rs
@@ -340,9 +340,8 @@ impl NetworkEventActor {
         // TODO: Send the correct values for all these fields.
         let hSizeOption = self.response.headers.as_ref().map(|headers| headers.len() as u32);
         let hSize = hSizeOption.unwrap_or(0);
-        let (status_code, status_message) =
-            self.response.status.as_ref().map(|&RawStatus(ref code, ref text)| (*code, text.clone().into_owned())).
-                unwrap_or((0, "".to_owned()));
+        let (status_code, status_message) = self.response.status.as_ref().
+                map_or((0, "".to_owned()), |&RawStatus(ref code, ref text)| (*code, text.clone().into_owned()));
         // TODO: Send the correct values for remoteAddress and remotePort and http_version.
         ResponseStartMsg {
             httpVersion: "HTTP/1.1".to_owned(),
diff --git a/components/devtools/protocol.rs b/components/devtools/protocol.rs
index 8a338f98091..007f26dae96 100644
--- a/components/devtools/protocol.rs
+++ b/components/devtools/protocol.rs
@@ -14,18 +14,18 @@ use std::io::{Read, Write};
 use std::net::TcpStream;
 
 pub trait JsonPacketStream {
-    fn write_json_packet<'a, T: Encodable>(&mut self, obj: &T);
+    fn write_json_packet<T: Encodable>(&mut self, obj: &T);
     fn read_json_packet(&mut self) -> Result<Option<Json>, String>;
 }
 
 impl JsonPacketStream for TcpStream {
-    fn write_json_packet<'a, T: Encodable>(&mut self, obj: &T) {
+    fn write_json_packet<T: Encodable>(&mut self, obj: &T) {
         let s = json::encode(obj).unwrap().replace("__type__", "type");
         println!("<- {}", s);
         write!(self, "{}:{}", s.len(), s).unwrap();
     }
 
-    fn read_json_packet<'a>(&mut self) -> Result<Option<Json>, String> {
+    fn read_json_packet(&mut self) -> Result<Option<Json>, String> {
         // https://wiki.mozilla.org/Remote_Debugging_Protocol_Stream_Transport
         // In short, each JSON packet is [ascii length]:[JSON data of given length]
         let mut buffer = vec!();
diff --git a/components/gfx/display_list/mod.rs b/components/gfx/display_list/mod.rs
index 3a264d10147..9763e882585 100644
--- a/components/gfx/display_list/mod.rs
+++ b/components/gfx/display_list/mod.rs
@@ -941,7 +941,7 @@ impl StackingContextLayerCreator {
             return Some(LayerInfo::new(layer.id, ScrollPolicy::Scrollable, None));
         }
 
-        return self.last_child_layer_info;
+        self.last_child_layer_info
     }
 
     #[inline]
diff --git a/components/gfx/font_cache_task.rs b/components/gfx/font_cache_task.rs
index aba00250ba1..b7ba44b4b3a 100644
--- a/components/gfx/font_cache_task.rs
+++ b/components/gfx/font_cache_task.rs
@@ -39,7 +39,7 @@ impl FontTemplates {
     }
 
     /// Find a font in this family that matches a given descriptor.
-    fn find_font_for_style<'a>(&'a mut self, desc: &FontTemplateDescriptor, fctx: &FontContextHandle)
+    fn find_font_for_style(&mut self, desc: &FontTemplateDescriptor, fctx: &FontContextHandle)
                                -> Option<Arc<FontTemplateData>> {
         // TODO(Issue #189): optimize lookup for
         // regular/bold/italic/bolditalic with fixed offsets and a
@@ -251,7 +251,7 @@ impl FontCache {
         }
     }
 
-    fn find_font_in_local_family<'a>(&'a mut self, family_name: &LowercaseString, desc: &FontTemplateDescriptor)
+    fn find_font_in_local_family(&mut self, family_name: &LowercaseString, desc: &FontTemplateDescriptor)
                                 -> Option<Arc<FontTemplateData>> {
         // TODO(Issue #188): look up localized font family names if canonical name not found
         // look up canonical name
@@ -275,14 +275,13 @@ impl FontCache {
         }
     }
 
-    fn find_font_in_web_family<'a>(&'a mut self, family: &FontFamily, desc: &FontTemplateDescriptor)
+    fn find_font_in_web_family(&mut self, family: &FontFamily, desc: &FontTemplateDescriptor)
                                 -> Option<Arc<FontTemplateData>> {
         let family_name = LowercaseString::new(family.name());
 
         if self.web_families.contains_key(&family_name) {
             let templates = self.web_families.get_mut(&family_name).unwrap();
-            let maybe_font = templates.find_font_for_style(desc, &self.font_context);
-            maybe_font
+            templates.find_font_for_style(desc, &self.font_context)
         } else {
             None
         }
diff --git a/components/gfx/platform/freetype/font.rs b/components/gfx/platform/freetype/font.rs
index 66769d200cd..282bd72944f 100644
--- a/components/gfx/platform/freetype/font.rs
+++ b/components/gfx/platform/freetype/font.rs
@@ -166,12 +166,12 @@ impl FontHandleMethods for FontHandle {
         assert!(!self.face.is_null());
         unsafe {
             let idx = FT_Get_Char_Index(self.face, codepoint as FT_ULong);
-            return if idx != 0 as FT_UInt {
+            if idx != 0 as FT_UInt {
                 Some(idx as GlyphId)
             } else {
                 debug!("Invalid codepoint: {}", codepoint);
                 None
-            };
+            }
         }
     }
 
@@ -196,10 +196,10 @@ impl FontHandleMethods for FontHandle {
                 let advance = (*slot).metrics.horiAdvance;
                 debug!("h_advance for {} is {}", glyph, advance);
                 let advance = advance as i32;
-                return Some(fixed_to_float_ft(advance) as FractionalPixel);
+                Some(fixed_to_float_ft(advance) as FractionalPixel)
             } else {
                 debug!("Unable to load glyph {}. reason: {}", glyph, res);
-                return None;
+                None
             }
         }
     }
@@ -239,8 +239,7 @@ impl FontHandleMethods for FontHandle {
 
         let average_advance = self.glyph_index('0')
                                   .and_then(|idx| self.glyph_h_advance(idx))
-                                  .map(|advance| self.font_units_to_au(advance))
-                                  .unwrap_or(max_advance);
+                                  .map_or(max_advance, |advance| self.font_units_to_au(advance));
 
         let metrics = FontMetrics {
             underline_size:   underline_size,
@@ -258,7 +257,7 @@ impl FontHandleMethods for FontHandle {
         };
 
         debug!("Font metrics (@{}px): {:?}", em_size.to_f32_px(), metrics);
-        return metrics;
+        metrics
     }
 
     fn table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
@@ -310,6 +309,6 @@ impl<'a> FontHandle {
         // If this isn't true then we're scaling one of the axes wrong
         assert!(metrics.x_ppem == metrics.y_ppem);
 
-        return Au::from_f64_px(value * x_scale);
+        Au::from_f64_px(value * x_scale)
     }
 }
diff --git a/components/layout/block.rs b/components/layout/block.rs
index 5b34977b484..7de0d52ef42 100644
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@@ -1520,12 +1520,10 @@ impl BlockFlow {
     }
 
     fn determine_if_layer_needed(&mut self) {
-        if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) {
-            // Fixed position layers get layers.
-            if self.is_fixed() {
-                self.base.flags.insert(NEEDS_LAYER);
-                return
-            }
+        // Fixed position layers get layers.
+        if self.base.flags.contains(IS_ABSOLUTELY_POSITIONED) && self.is_fixed() {
+            self.base.flags.insert(NEEDS_LAYER);
+            return
         }
 
         // This flow needs a layer if it has a 3d transform, or provides perspective
diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index 6e6ea30332c..89c895ca4f2 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -1102,12 +1102,9 @@ impl<'a, 'ln, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode<'ln>>
                                                              node,
                                                              caption_side::T::top);
 
-        match construction_result {
-            ConstructionResult::Flow(table_flow, table_abs_descendants) => {
-                wrapper_flow.add_new_child(table_flow);
-                abs_descendants.push_descendants(table_abs_descendants);
-            }
-            _ => {}
+        if let ConstructionResult::Flow(table_flow, table_abs_descendants) = construction_result {
+            wrapper_flow.add_new_child(table_flow);
+            abs_descendants.push_descendants(table_abs_descendants);
         }
 
         // If the value of `caption-side` is `bottom`, place it now.
@@ -1271,12 +1268,9 @@ impl<'a, 'ln, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode<'ln>>
         for kid in node.children() {
             // CSS 2.1 § 17.2.1. Treat all non-column child fragments of `table-column-group`
             // as `display: none`.
-            match kid.swap_out_construction_result() {
-                ConstructionResult::ConstructionItem(ConstructionItem::TableColumnFragment(
-                        fragment)) => {
-                    col_fragments.push(fragment);
-                }
-                _ => {}
+            if let ConstructionResult::ConstructionItem(ConstructionItem::TableColumnFragment(fragment))
+                   = kid.swap_out_construction_result() {
+                col_fragments.push(fragment)
             }
         }
         if col_fragments.is_empty() {
diff --git a/components/layout/css/matching.rs b/components/layout/css/matching.rs
index e83899e2893..bffd6188344 100644
--- a/components/layout/css/matching.rs
+++ b/components/layout/css/matching.rs
@@ -236,24 +236,20 @@ impl<'le, ConcreteElement> PrivateElementMatchMethods<'le, ConcreteElement>
         let parent_data: Option<&PrivateStyleData> = unsafe {
             parent_node.borrow_data_unchecked().map(|d| &*d)
         };
-        match parent_data {
-            Some(parent_data_ref) => {
-                // Check parent style.
-                let parent_style = (*parent_data_ref).style.as_ref().unwrap();
-                if !arc_ptr_eq(parent_style, &candidate.parent_style) {
-                    return None
-                }
-
-                // Check tag names, classes, etc.
-                if !candidate.can_share_style_with(self) {
-                    return None
-                }
+        if let Some(parent_data_ref) = parent_data {
+            // Check parent style.
+            let parent_style = (*parent_data_ref).style.as_ref().unwrap();
+            if !arc_ptr_eq(parent_style, &candidate.parent_style) {
+                return None
+            }
 
-                return Some(candidate.style.clone())
+            // Check tag names, classes, etc.
+            if !candidate.can_share_style_with(self) {
+                return None
             }
-            _ => {}
-        }
 
+            return Some(candidate.style.clone())
+        }
         None
     }
 }
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index cf88e24aba3..828cdeabf8d 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -2006,24 +2006,18 @@ impl Fragment {
     }
 
     pub fn update_late_computed_inline_position_if_necessary(&mut self) {
-        match self.specific {
-            SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
-                let position = self.border_box.start.i;
-                flow_ref::deref_mut(&mut info.flow_ref)
-                    .update_late_computed_inline_position_if_necessary(position)
-            }
-            _ => {}
+        if let SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) = self.specific {
+            let position = self.border_box.start.i;
+            flow_ref::deref_mut(&mut info.flow_ref)
+                .update_late_computed_inline_position_if_necessary(position)
         }
     }
 
     pub fn update_late_computed_block_position_if_necessary(&mut self) {
-        match self.specific {
-            SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) => {
-                let position = self.border_box.start.b;
-                flow_ref::deref_mut(&mut info.flow_ref)
-                    .update_late_computed_block_position_if_necessary(position)
-            }
-            _ => {}
+        if let SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut info) = self.specific {
+            let position = self.border_box.start.b;
+            flow_ref::deref_mut(&mut info.flow_ref)
+                .update_late_computed_block_position_if_necessary(position)
         }
     }
 
diff --git a/components/layout/generated_content.rs b/components/layout/generated_content.rs
index 686d9ec3920..fd1f1d2f219 100644
--- a/components/layout/generated_content.rs
+++ b/components/layout/generated_content.rs
@@ -302,9 +302,9 @@ impl<'a,'b> ResolveGeneratedContentFragmentMutator<'a,'b> {
                 &quotes.0[self.traversal.quote as usize]
             };
         if close {
-            close_quote.to_string()
+            close_quote.clone()
         } else {
-            open_quote.to_string()
+            open_quote.clone()
         }
     }
 }
diff --git a/components/layout/layout_task.rs b/components/layout/layout_task.rs
index da3b7518f3f..88425fde26b 100644
--- a/components/layout/layout_task.rs
+++ b/components/layout/layout_task.rs
@@ -654,7 +654,7 @@ impl LayoutTask {
         // FIXME(njn): Just measuring the display tree for now.
         let rw_data = possibly_locked_rw_data.lock();
         let stacking_context = rw_data.stacking_context.as_ref();
-        let ref formatted_url = format!("url({})", *self.url.borrow());
+        let formatted_url = &format!("url({})", *self.url.borrow());
         reports.push(Report {
             path: path![formatted_url, "layout-task", "display-list"],
             kind: ReportKind::ExplicitJemallocHeapSize,
@@ -731,7 +731,7 @@ impl LayoutTask {
 
     /// Shuts down the layout task now. If there are any DOM nodes left, layout will now (safely)
     /// crash.
-    fn exit_now<'a, 'b>(&mut self) {
+    fn exit_now(&mut self) {
         if let Some(ref mut traversal) = self.parallel_traversal {
             traversal.shutdown()
         }
diff --git a/components/layout/query.rs b/components/layout/query.rs
index ff084a1adf8..1b1f0907a4b 100644
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@@ -480,7 +480,7 @@ pub fn process_resolved_style_request<'ln, N: LayoutNode<'ln>>(
             requested_node: N,
             property: &Atom) -> Option<String> {
         let maybe_data = layout_node.borrow_layout_data();
-        let position = maybe_data.map(|data| {
+        let position = maybe_data.map_or(Point2D::zero(), |data| {
             match (*data).flow_construction_result {
                 ConstructionResult::Flow(ref flow_ref, _) =>
                     flow::base(flow_ref.deref()).stacking_relative_position,
@@ -488,7 +488,7 @@ pub fn process_resolved_style_request<'ln, N: LayoutNode<'ln>>(
                 // https://github.com/servo/servo/issues/8307
                 _ => Point2D::zero()
             }
-        }).unwrap_or(Point2D::zero());
+        });
         let property = match *property {
             atom!("bottom") => PositionProperty::Bottom,
             atom!("top") => PositionProperty::Top,
diff --git a/components/layout/table_row.rs b/components/layout/table_row.rs
index 731285221f7..c3b318acd61 100644
--- a/components/layout/table_row.rs
+++ b/components/layout/table_row.rs
@@ -747,33 +747,27 @@ fn set_inline_position_of_child_flow(
                 inline_start_border: border_collapse_info.collapsed_borders_for_row
                                                          .inline
                                                          .get(child_index)
-                                                         .map(|x| *x)
-                                                         .unwrap_or(CollapsedBorder::new()),
+                                                         .map_or(CollapsedBorder::new(), |x| *x),
                 inline_end_border: border_collapse_info.collapsed_borders_for_row
                                                        .inline
                                                        .get(child_index + 1)
-                                                       .map(|x| *x)
-                                                       .unwrap_or(CollapsedBorder::new()),
+                                                       .map_or(CollapsedBorder::new(), |x| *x),
                 block_start_border: border_collapse_info.collapsed_borders_for_row
                                                         .block_start
                                                         .get(child_index)
-                                                        .map(|x| *x)
-                                                        .unwrap_or(CollapsedBorder::new()),
+                                                        .map_or(CollapsedBorder::new(), |x| *x),
                 block_end_border: border_collapse_info.collapsed_borders_for_row
                                                       .block_end
                                                       .get(child_index)
-                                                      .map(|x| *x)
-                                                      .unwrap_or(CollapsedBorder::new()),
+                                                      .map_or(CollapsedBorder::new(), |x| *x),
                 inline_start_width: border_collapse_info.collapsed_border_spacing_for_row
                                                         .inline
                                                         .get(child_index)
-                                                        .map(|x| *x)
-                                                        .unwrap_or(Au(0)),
+                                                        .map_or(Au(0), |x| *x),
                 inline_end_width: border_collapse_info.collapsed_border_spacing_for_row
                                                       .inline
                                                       .get(child_index + 1)
-                                                      .map(|x| *x)
-                                                      .unwrap_or(Au(0)),
+                                                      .map_or(Au(0), |x| *x),
                 block_start_width: border_collapse_info.collapsed_border_spacing_for_row
                                                        .block_start,
                 block_end_width: border_collapse_info.collapsed_border_spacing_for_row.block_end,
diff --git a/components/layout/text.rs b/components/layout/text.rs
index b561b8d5da1..d28cea4c0e2 100644
--- a/components/layout/text.rs
+++ b/components/layout/text.rs
@@ -38,15 +38,12 @@ fn text(fragments: &LinkedList<Fragment>) -> String {
     let mut text = String::new();
 
     for fragment in fragments {
-        match fragment.specific {
-            SpecificFragmentInfo::UnscannedText(ref info) => {
-                if fragment.white_space().preserve_newlines() {
-                    text.push_str(&info.text);
-                } else {
-                    text.push_str(&info.text.replace("\n", " "));
-                }
+        if let SpecificFragmentInfo::UnscannedText(ref info) = fragment.specific {
+            if fragment.white_space().preserve_newlines() {
+                text.push_str(&info.text);
+            } else {
+                text.push_str(&info.text.replace("\n", " "));
             }
-            _ => {}
         }
     }
     text
diff --git a/components/layout/wrapper.rs b/components/layout/wrapper.rs
index c2092a81e21..147fda916e3 100644
--- a/components/layout/wrapper.rs
+++ b/components/layout/wrapper.rs
@@ -198,7 +198,7 @@ impl<'ln> TNode<'ln> for ServoLayoutNode<'ln> {
     }
 
     fn as_document(&self) -> Option<ServoLayoutDocument<'ln>> {
-        self.node.downcast().map(|document| ServoLayoutDocument::from_layout_js(document))
+        self.node.downcast().map(ServoLayoutDocument::from_layout_js)
     }
 
     fn has_changed(&self) -> bool {
@@ -432,7 +432,7 @@ impl<'le> ServoLayoutElement<'le> {
 }
 
 fn as_element<'le>(node: LayoutJS<Node>) -> Option<ServoLayoutElement<'le>> {
-    node.downcast().map(|element| ServoLayoutElement::from_layout_js(element))
+    node.downcast().map(ServoLayoutElement::from_layout_js)
 }
 
 macro_rules! state_getter {
diff --git a/components/net/cookie.rs b/components/net/cookie.rs
index b496eb7256e..2f555767b11 100644
--- a/components/net/cookie.rs
+++ b/components/net/cookie.rs
@@ -39,7 +39,7 @@ impl Cookie {
             _ => (false, None)
         };
 
-        let url_host = request.host().map(|host| host.serialize()).unwrap_or("".to_owned());
+        let url_host = request.host().map_or("".to_owned(), |host| host.serialize());
 
         // Step 4
         let mut domain = cookie.domain.clone().unwrap_or("".to_owned());
diff --git a/components/net/cookie_storage.rs b/components/net/cookie_storage.rs
index 69f3eed37f6..4179d3ceda7 100644
--- a/components/net/cookie_storage.rs
+++ b/components/net/cookie_storage.rs
@@ -69,8 +69,8 @@ impl CookieStorage {
     }
 
     pub fn cookie_comparator(a: &Cookie, b: &Cookie) -> Ordering {
-        let a_path_len = a.cookie.path.as_ref().map(|p| p.len()).unwrap_or(0);
-        let b_path_len = b.cookie.path.as_ref().map(|p| p.len()).unwrap_or(0);
+        let a_path_len = a.cookie.path.as_ref().map_or(0, |p| p.len());
+        let b_path_len = b.cookie.path.as_ref().map_or(0, |p| p.len());
         match a_path_len.cmp(&b_path_len) {
             Ordering::Equal => {
                 let a_creation_time = a.creation_time.to_timespec();
diff --git a/components/net/http_loader.rs b/components/net/http_loader.rs
index e7a5d0952e1..995c2e951b1 100644
--- a/components/net/http_loader.rs
+++ b/components/net/http_loader.rs
@@ -178,7 +178,7 @@ pub trait HttpResponse: Read {
     fn status(&self) -> StatusCode;
     fn status_raw(&self) -> &RawStatus;
     fn http_version(&self) -> String {
-        return "HTTP/1.1".to_owned()
+        "HTTP/1.1".to_owned()
     }
     fn content_encoding(&self) -> Option<Encoding> {
         self.headers().get::<ContentEncoding>().and_then(|h| {
@@ -295,11 +295,8 @@ impl HttpRequest for WrappedHttpRequest {
         };
 
         if let Some(ref data) = *body {
-            match request_writer.write_all(&data) {
-                Err(e) => {
-                    return Err(LoadError::Connection(url, e.description().to_owned()))
-                }
-                _ => {}
+            if let Err(e) = request_writer.write_all(&data) {
+                return Err(LoadError::Connection(url, e.description().to_owned()))
             }
         }
 
diff --git a/components/net_traits/hosts.rs b/components/net_traits/hosts.rs
index a5e35f8220b..3d80344fd00 100644
--- a/components/net_traits/hosts.rs
+++ b/components/net_traits/hosts.rs
@@ -61,9 +61,9 @@ pub fn parse_hostsfile(hostsfile_content: &str) -> Box<HashMap<String, String>>
 
 pub fn replace_hosts(url: &Url) -> Url {
     unsafe {
-        HOST_TABLE.map(|host_table| {
+        HOST_TABLE.map_or_else(|| url.clone(), |host_table| {
             host_replacement(host_table, url)
-        }).unwrap_or_else(|| url.clone())
+        })
     }
 }
 
diff --git a/components/profile/mem.rs b/components/profile/mem.rs
index 8a9314c69c1..033a1421421 100644
--- a/components/profile/mem.rs
+++ b/components/profile/mem.rs
@@ -649,8 +649,7 @@ mod system_reporter {
         // Note that the sum of all these segments' RSS values differs from the "resident"
         // measurement obtained via /proc/<pid>/statm in resident(). It's unclear why this
         // difference occurs; for some processes the measurements match, but for Servo they do not.
-        let segs: Vec<(String, usize)> = seg_map.into_iter().collect();
-        segs
+        seg_map.into_iter().collect()
     }
 
     #[cfg(not(target_os = "linux"))]
diff --git a/components/profile/time.rs b/components/profile/time.rs
index d4495c48bd4..22f888256bf 100644
--- a/components/profile/time.rs
+++ b/components/profile/time.rs
@@ -172,9 +172,10 @@ impl Profiler {
                 let mut start_energy = read_energy_uj();
                 loop {
                     for _ in 0..loop_count {
-                        match run_ap_thread() {
-                            true => thread::sleep(Duration::from_millis(SLEEP_MS as u64)),
-                            false => return,
+                        if run_ap_thread() {
+                            thread::sleep(Duration::from_millis(SLEEP_MS as u64))
+                        } else {
+                            return
                         }
                     }
                     let end_time = precise_time_ns();
@@ -258,7 +259,7 @@ impl Profiler {
             let data_len = data.len();
             if data_len > 0 {
                 let (mean, median, min, max) =
-                    (data.iter().map(|&x|x).sum::<f64>() / (data_len as f64),
+                    (data.iter().sum::<f64>() / (data_len as f64),
                      data[data_len / 2],
                      data.iter().fold(f64::INFINITY, |a, &b| a.min(b)),
                      data.iter().fold(-f64::INFINITY, |a, &b| a.max(b)));
diff --git a/components/script/cors.rs b/components/script/cors.rs
index 8e3b2b2b4c5..786d12d94ae 100644
--- a/components/script/cors.rs
+++ b/components/script/cors.rs
@@ -92,10 +92,9 @@ impl CORSRequest {
            method: Method,
            headers: Headers)
            -> CORSRequest {
-        match referer.scheme_data {
-            SchemeData::Relative(ref mut data) => data.path = vec![],
-            _ => {}
-        };
+        if let SchemeData::Relative(ref mut data) = referer.scheme_data {
+            data.path = vec![];
+        }
         referer.fragment = None;
         referer.query = None;
         CORSRequest {
@@ -167,12 +166,11 @@ impl CORSRequest {
         let cache = &mut CORSCache(vec!()); // XXXManishearth Should come from user agent
         if self.preflight_flag &&
            !cache.match_method(self, &self.method) &&
-           !self.headers.iter().all(|h| is_simple_header(&h) && cache.match_header(self, h.name())) {
-            if !is_simple_method(&self.method) || self.mode == RequestMode::ForcedPreflight {
-                return self.preflight_fetch();
-                // Everything after this is part of XHR::fetch()
-                // Expect the organization of code to improve once we have a fetch crate
-            }
+           !self.headers.iter().all(|h| is_simple_header(&h) && cache.match_header(self, h.name())) &&
+           (!is_simple_method(&self.method) || self.mode == RequestMode::ForcedPreflight) {
+            return self.preflight_fetch();
+            // Everything after this is part of XHR::fetch()
+            // Expect the organization of code to improve once we have a fetch crate
         }
         response
     }
@@ -398,12 +396,11 @@ impl CORSCache {
         self.cleanup();
         let CORSCache(ref mut buf) = *self;
         // Credentials are not yet implemented here
-        let entry = buf.iter_mut().find(|e| {
+        buf.iter_mut().find(|e| {
             e.origin.scheme == request.origin.scheme && e.origin.host() == request.origin.host() &&
             e.origin.port() == request.origin.port() && e.url == request.destination &&
             e.header_or_method.match_header(header_name)
-        });
-        entry
+        })
     }
 
     fn match_header(&mut self, request: &CORSRequest, header_name: &str) -> bool {
@@ -426,12 +423,11 @@ impl CORSCache {
         self.cleanup();
         let CORSCache(ref mut buf) = *self;
         // Credentials are not yet implemented here
-        let entry = buf.iter_mut().find(|e| {
+        buf.iter_mut().find(|e| {
             e.origin.scheme == request.origin.scheme && e.origin.host() == request.origin.host() &&
             e.origin.port() == request.origin.port() && e.url == request.destination &&
             e.header_or_method.match_method(method)
-        });
-        entry
+        })
     }
 
     /// https://fetch.spec.whatwg.org/#concept-cache-match-method
diff --git a/components/script/dom/attr.rs b/components/script/dom/attr.rs
index 9a3593f20d8..34cb8537c86 100644
--- a/components/script/dom/attr.rs
+++ b/components/script/dom/attr.rs
@@ -191,7 +191,7 @@ impl Attr {
     /// Sets the owner element. Should be called after the attribute is added
     /// or removed from its older parent.
     pub fn set_owner(&self, owner: Option<&Element>) {
-        let ref ns = self.identifier.namespace;
+        let ns = &self.identifier.namespace;
         match (self.owner().r(), owner) {
             (None, Some(new)) => {
                 // Already in the list of attributes of new owner.
diff --git a/components/script/dom/bindings/js.rs b/components/script/dom/bindings/js.rs
index 247a59180e4..dfe1acca376 100644
--- a/components/script/dom/bindings/js.rs
+++ b/components/script/dom/bindings/js.rs
@@ -486,7 +486,7 @@ impl RootCollection {
     }
 
     /// Start tracking a stack-based root
-    fn root<'b>(&self, untracked_reflector: *const Reflector) {
+    fn root(&self, untracked_reflector: *const Reflector) {
         debug_assert!(task_state::get().is_script());
         unsafe {
             let mut roots = &mut *self.roots.get();
@@ -496,7 +496,7 @@ impl RootCollection {
     }
 
     /// Stop tracking a stack-based root, asserting if the reflector isn't found
-    fn unroot<'b, T: Reflectable>(&self, rooted: &Root<T>) {
+    fn unroot<T: Reflectable>(&self, rooted: &Root<T>) {
         debug_assert!(task_state::get().is_script());
         unsafe {
             let mut roots = &mut *self.roots.get();
diff --git a/components/script/dom/bindings/xmlname.rs b/components/script/dom/bindings/xmlname.rs
index 957de10c9eb..6975fb8d702 100644
--- a/components/script/dom/bindings/xmlname.rs
+++ b/components/script/dom/bindings/xmlname.rs
@@ -148,9 +148,10 @@ pub fn xml_name_type(name: &str) -> XMLName {
             return XMLName::InvalidXMLName;
         }
         if c == ':' {
-            match seen_colon {
-                true => non_qname_colons = true,
-                false => seen_colon = true,
+            if seen_colon {
+                non_qname_colons = true;
+            } else {
+                seen_colon = true;
             }
         }
         last = c
@@ -160,9 +161,10 @@ pub fn xml_name_type(name: &str) -> XMLName {
         non_qname_colons = true
     }
 
-    match non_qname_colons {
-        false => XMLName::QName,
-        true => XMLName::Name,
+    if non_qname_colons {
+        XMLName::Name
+    } else {
+        XMLName::QName
     }
 }
 
diff --git a/components/script/dom/canvasrenderingcontext2d.rs b/components/script/dom/canvasrenderingcontext2d.rs
index 2cf1b4e0fd7..42733bbe526 100644
--- a/components/script/dom/canvasrenderingcontext2d.rs
+++ b/components/script/dom/canvasrenderingcontext2d.rs
@@ -320,10 +320,8 @@ impl CanvasRenderingContext2D {
             }
         };
 
-        if result.is_ok() {
-            if !self.is_origin_clean(image) {
-                self.set_origin_unclean()
-            }
+        if result.is_ok() && !self.is_origin_clean(image) {
+            self.set_origin_unclean()
         }
         result
     }
diff --git a/components/script/dom/cssstyledeclaration.rs b/components/script/dom/cssstyledeclaration.rs
index cbffda3e834..12d3425d520 100644
--- a/components/script/dom/cssstyledeclaration.rs
+++ b/components/script/dom/cssstyledeclaration.rs
@@ -137,7 +137,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
             }
         });
 
-        result.map(DOMString::from).unwrap_or(DOMString::new())
+        result.map_or(DOMString::new(), DOMString::from)
     }
 
     // https://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-getpropertyvalue
@@ -175,11 +175,10 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         }
 
         // Step 3 & 4
-        let result = match owner.get_inline_style_declaration(&property) {
+        match owner.get_inline_style_declaration(&property) {
             Some(declaration) => DOMString::from(declaration.value()),
             None => DOMString::new(),
-        };
-        result
+        }
     }
 
     // https://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-getpropertypriority
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 6fe811ef168..f2593121c6c 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -1926,9 +1926,10 @@ impl DocumentMethods for Document {
         }
 
         // Step 2.
-        let clone_children = match deep {
-            true => CloneChildrenFlag::CloneChildren,
-            false => CloneChildrenFlag::DoNotCloneChildren,
+        let clone_children = if deep {
+            CloneChildrenFlag::CloneChildren
+        } else {
+            CloneChildrenFlag::DoNotCloneChildren
         };
 
         Ok(Node::clone(node, Some(self), clone_children))
@@ -2325,7 +2326,7 @@ impl DocumentMethods for Document {
         let (tx, rx) = ipc::channel().unwrap();
         let _ = self.window.resource_task().send(GetCookiesForUrl((*url).clone(), tx, NonHTTP));
         let cookies = rx.recv().unwrap();
-        Ok(cookies.map(DOMString::from).unwrap_or(DOMString::from("")))
+        Ok(cookies.map_or(DOMString::new(), DOMString::from))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-document-cookie
diff --git a/components/script/dom/domtokenlist.rs b/components/script/dom/domtokenlist.rs
index dd7eb17ba74..fd1644f17c7 100644
--- a/components/script/dom/domtokenlist.rs
+++ b/components/script/dom/domtokenlist.rs
@@ -54,10 +54,10 @@ impl DOMTokenList {
 impl DOMTokenListMethods for DOMTokenList {
     // https://dom.spec.whatwg.org/#dom-domtokenlist-length
     fn Length(&self) -> u32 {
-        self.attribute().map(|attr| {
+        self.attribute().map_or(0, |attr| {
             let attr = attr.r();
             attr.value().as_tokens().len()
-        }).unwrap_or(0) as u32
+        }) as u32
     }
 
     // https://dom.spec.whatwg.org/#dom-domtokenlist-item
@@ -71,13 +71,13 @@ impl DOMTokenListMethods for DOMTokenList {
     // https://dom.spec.whatwg.org/#dom-domtokenlist-contains
     fn Contains(&self, token: DOMString) -> Fallible<bool> {
         self.check_token_exceptions(&token).map(|token| {
-            self.attribute().map(|attr| {
+            self.attribute().map_or(false, |attr| {
                 let attr = attr.r();
                 attr.value()
                     .as_tokens()
                     .iter()
                     .any(|atom: &Atom| *atom == token)
-            }).unwrap_or(false)
+            })
         })
     }
 
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 5d500b9ef75..ed901d5cdf8 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -924,9 +924,8 @@ impl Element {
     // https://html.spec.whatwg.org/multipage/#attr-data-*
     pub fn set_custom_attribute(&self, name: DOMString, value: DOMString) -> ErrorResult {
         // Step 1.
-        match xml_name_type(&name) {
-            InvalidXMLName => return Err(Error::InvalidCharacter),
-            _ => {}
+        if let InvalidXMLName = xml_name_type(&name) {
+            return Err(Error::InvalidCharacter);
         }
 
         // Steps 2-5.
@@ -1012,8 +1011,7 @@ impl Element {
             }
         };
         self.get_attribute(&ns!(), &atom!("class"))
-            .map(|attr| attr.value().as_tokens().iter().any(|atom| is_equal(name, atom)))
-            .unwrap_or(false)
+            .map_or(false, |attr| attr.value().as_tokens().iter().any(|atom| is_equal(name, atom)))
     }
 
     pub fn set_atomic_attribute(&self, local_name: &Atom, value: DOMString) {
@@ -1884,10 +1882,11 @@ impl Element {
         }
         let node = self.upcast::<Node>();
         node.owner_doc().element_state_will_change(self);
-        match value {
-            true => state.insert(which),
-            false => state.remove(which),
-        };
+        if value {
+            state.insert(which);
+        } else {
+            state.remove(which);
+        }
         self.state.set(state);
     }
 
diff --git a/components/script/dom/eventtarget.rs b/components/script/dom/eventtarget.rs
index 94998185507..ae264060107 100644
--- a/components/script/dom/eventtarget.rs
+++ b/components/script/dom/eventtarget.rs
@@ -355,24 +355,21 @@ impl EventTargetMethods for EventTarget {
                         ty: DOMString,
                         listener: Option<Rc<EventListener>>,
                         capture: bool) {
-        match listener {
-            Some(listener) => {
-                let mut handlers = self.handlers.borrow_mut();
-                let entry = match handlers.entry(Atom::from(&*ty)) {
-                    Occupied(entry) => entry.into_mut(),
-                    Vacant(entry) => entry.insert(vec!()),
-                };
-
-                let phase = if capture { ListenerPhase::Capturing } else { ListenerPhase::Bubbling };
-                let new_entry = EventListenerEntry {
-                    phase: phase,
-                    listener: EventListenerType::Additive(listener)
-                };
-                if !entry.contains(&new_entry) {
-                    entry.push(new_entry);
-                }
-            },
-            _ => (),
+        if let Some(listener) = listener {
+            let mut handlers = self.handlers.borrow_mut();
+            let entry = match handlers.entry(Atom::from(&*ty)) {
+                Occupied(entry) => entry.into_mut(),
+                Vacant(entry) => entry.insert(vec!()),
+            };
+
+            let phase = if capture { ListenerPhase::Capturing } else { ListenerPhase::Bubbling };
+            let new_entry = EventListenerEntry {
+                phase: phase,
+                listener: EventListenerType::Additive(listener)
+            };
+            if !entry.contains(&new_entry) {
+                entry.push(new_entry);
+            }
         }
     }
 
@@ -381,22 +378,19 @@ impl EventTargetMethods for EventTarget {
                            ty: DOMString,
                            listener: Option<Rc<EventListener>>,
                            capture: bool) {
-        match listener {
-            Some(ref listener) => {
-                let mut handlers = self.handlers.borrow_mut();
-                let entry = handlers.get_mut(&Atom::from(&*ty));
-                for entry in entry {
-                    let phase = if capture { ListenerPhase::Capturing } else { ListenerPhase::Bubbling };
-                    let old_entry = EventListenerEntry {
-                        phase: phase,
-                        listener: EventListenerType::Additive(listener.clone())
-                    };
-                    if let Some(position) = entry.iter().position(|e| *e == old_entry) {
-                        entry.remove(position);
-                    }
+        if let Some(ref listener) = listener {
+            let mut handlers = self.handlers.borrow_mut();
+            let entry = handlers.get_mut(&Atom::from(&*ty));
+            for entry in entry {
+                let phase = if capture { ListenerPhase::Capturing } else { ListenerPhase::Bubbling };
+                let old_entry = EventListenerEntry {
+                    phase: phase,
+                    listener: EventListenerType::Additive(listener.clone())
+                };
+                if let Some(position) = entry.iter().position(|e| *e == old_entry) {
+                    entry.remove(position);
                 }
-            },
-            _ => (),
+            }
         }
     }
 
diff --git a/components/script/dom/htmlcollection.rs b/components/script/dom/htmlcollection.rs
index 9eb375dc89b..1e80481ac68 100644
--- a/components/script/dom/htmlcollection.rs
+++ b/components/script/dom/htmlcollection.rs
@@ -287,8 +287,8 @@ impl<'a> Iterator for HTMLCollectionElementsIter<'a> {
     type Item = Root<Element>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let ref filter = self.filter;
-        let ref root = self.root;
+        let filter = &self.filter;
+        let root = &self.root;
         self.node_iter.by_ref()
                       .filter_map(Root::downcast)
                       .filter(|element| filter.filter(&element, root))
@@ -306,8 +306,8 @@ impl<'a> Iterator for HTMLCollectionElementsRevIter<'a> {
     type Item = Root<Element>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let ref filter = self.filter;
-        let ref root = self.root;
+        let filter = &self.filter;
+        let root = &self.root;
         self.node_iter.by_ref()
             .filter_map(Root::downcast)
             .filter(|element| filter.filter(&element, root))
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index a53c37f84e4..536b1e46c73 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -307,40 +307,37 @@ impl HTMLFormElement {
                     .any(|a| Root::downcast::<HTMLDataListElement>(a).is_some()) {
                 continue;
             }
-            match child.type_id() {
-                NodeTypeId::Element(ElementTypeId::HTMLElement(element)) => {
-                    match element {
-                        HTMLElementTypeId::HTMLInputElement => {
-                            let input = child.downcast::<HTMLInputElement>().unwrap();
-                            // Step 3.2-3.7
-                            if let Some(datum) = input.get_form_datum(submitter) {
-                                data_set.push(datum);
-                            }
-                        }
-                        HTMLElementTypeId::HTMLButtonElement |
-                        HTMLElementTypeId::HTMLObjectElement => {
-                            // Unimplemented
-                            ()
+            if let NodeTypeId::Element(ElementTypeId::HTMLElement(element)) = child.type_id() {
+                match element {
+                    HTMLElementTypeId::HTMLInputElement => {
+                        let input = child.downcast::<HTMLInputElement>().unwrap();
+                        // Step 3.2-3.7
+                        if let Some(datum) = input.get_form_datum(submitter) {
+                            data_set.push(datum);
                         }
-                        HTMLElementTypeId::HTMLSelectElement => {
-                            let select = child.downcast::<HTMLSelectElement>().unwrap();
-                            select.push_form_data(&mut data_set);
-                        }
-                        HTMLElementTypeId::HTMLTextAreaElement => {
-                            let textarea = child.downcast::<HTMLTextAreaElement>().unwrap();
-                            let name = textarea.Name();
-                            if !name.is_empty() {
-                                data_set.push(FormDatum {
-                                    ty: textarea.Type(),
-                                    name: name,
-                                    value: textarea.Value()
-                                });
-                            }
+                    }
+                    HTMLElementTypeId::HTMLButtonElement |
+                    HTMLElementTypeId::HTMLObjectElement => {
+                        // Unimplemented
+                        ()
+                    }
+                    HTMLElementTypeId::HTMLSelectElement => {
+                        let select = child.downcast::<HTMLSelectElement>().unwrap();
+                        select.push_form_data(&mut data_set);
+                    }
+                    HTMLElementTypeId::HTMLTextAreaElement => {
+                        let textarea = child.downcast::<HTMLTextAreaElement>().unwrap();
+                        let name = textarea.Name();
+                        if !name.is_empty() {
+                            data_set.push(FormDatum {
+                                ty: textarea.Type(),
+                                name: name,
+                                value: textarea.Value()
+                            });
                         }
-                        _ => ()
                     }
+                    _ => ()
                 }
-                _ => ()
             }
         }
         data_set
@@ -603,14 +600,11 @@ pub trait FormControl: DerivedFrom<Element> + Reflectable {
         if !owner.is_empty() {
             let doc = document_from_node(elem);
             let owner = doc.GetElementById(owner);
-            match owner {
-                Some(ref o) => {
-                    let maybe_form = o.downcast::<HTMLFormElement>();
-                    if maybe_form.is_some() {
-                        return maybe_form.map(Root::from_ref);
-                    }
-                },
-                _ => ()
+            if let Some(ref o) = owner {
+                let maybe_form = o.downcast::<HTMLFormElement>();
+                if maybe_form.is_some() {
+                    return maybe_form.map(Root::from_ref);
+                }
             }
         }
         elem.upcast::<Node>().ancestors().filter_map(Root::downcast).next()
diff --git a/components/script/dom/htmlinputelement.rs b/components/script/dom/htmlinputelement.rs
index 9413699ede7..7829d7e65b4 100644
--- a/components/script/dom/htmlinputelement.rs
+++ b/components/script/dom/htmlinputelement.rs
@@ -596,7 +596,7 @@ impl VirtualMethods for HTMLInputElement {
             &atom!("value") if !self.value_changed.get() => {
                 let value = mutation.new_value(attr).map(|value| (**value).to_owned());
                 self.textinput.borrow_mut().set_content(
-                    value.map(DOMString::from).unwrap_or(DOMString::from("")));
+                    value.map_or(DOMString::new(), DOMString::from));
             },
             &atom!("name") if self.input_type.get() == InputType::InputRadio => {
                 self.radio_group_updated(
@@ -663,9 +663,8 @@ impl VirtualMethods for HTMLInputElement {
         }
 
         if event.type_() == atom!("click") && !event.DefaultPrevented() {
-            match self.input_type.get() {
-                InputType::InputRadio => self.update_checked_state(true, true),
-                _ => {}
+            if let InputType::InputRadio = self.input_type.get() {
+                self.update_checked_state(true, true);
             }
 
             // TODO: Dispatch events for non activatable inputs
diff --git a/components/script/dom/htmllabelelement.rs b/components/script/dom/htmllabelelement.rs
index fb32405084d..01e05761cf2 100644
--- a/components/script/dom/htmllabelelement.rs
+++ b/components/script/dom/htmllabelelement.rs
@@ -49,7 +49,7 @@ impl Activatable for HTMLLabelElement {
     }
 
     fn is_instance_activatable(&self) -> bool {
-        return true;
+        true
     }
 
     // https://html.spec.whatwg.org/multipage/#run-pre-click-activation-steps
diff --git a/components/script/dom/htmlmetaelement.rs b/components/script/dom/htmlmetaelement.rs
index d39f37abd7a..fdba6dc7c3c 100644
--- a/components/script/dom/htmlmetaelement.rs
+++ b/components/script/dom/htmlmetaelement.rs
@@ -53,9 +53,8 @@ impl HTMLMetaElement {
             let name = name.value().to_ascii_lowercase();
             let name = name.trim_matches(HTML_SPACE_CHARACTERS);
 
-            match name {
-                "viewport" => self.apply_viewport(),
-                _ => {}
+            if name == "viewport" {
+                self.apply_viewport();
             }
         }
     }
diff --git a/components/script/dom/htmlscriptelement.rs b/components/script/dom/htmlscriptelement.rs
index 5a08c7c04b0..2bc483d1999 100644
--- a/components/script/dom/htmlscriptelement.rs
+++ b/components/script/dom/htmlscriptelement.rs
@@ -287,7 +287,7 @@ impl HTMLScriptElement {
                         }));
 
                         let (action_sender, action_receiver) = ipc::channel().unwrap();
-                        let listener = box NetworkListener {
+                        let listener = NetworkListener {
                             context: context,
                             script_chan: script_chan,
                         };
@@ -354,7 +354,7 @@ impl HTMLScriptElement {
                 parser.r().suspend();
             }
         }
-        return NextParserState::Suspend;
+        NextParserState::Suspend
     }
 
     pub fn is_ready_to_be_executed(&self) -> bool {
diff --git a/components/script/dom/htmltablecellelement.rs b/components/script/dom/htmltablecellelement.rs
index 81378a5a985..79cb31ced03 100644
--- a/components/script/dom/htmltablecellelement.rs
+++ b/components/script/dom/htmltablecellelement.rs
@@ -72,7 +72,7 @@ impl HTMLTableCellElementMethods for HTMLTableCellElement {
 
         parent_children.filter(|c| c.is::<HTMLTableCellElement>())
                        .position(|c| c.r() == self_node)
-                       .map(|p| p as i32).unwrap_or(-1)
+                       .map_or(-1, |p| p as i32)
     }
 }
 
diff --git a/components/script/dom/htmltextareaelement.rs b/components/script/dom/htmltextareaelement.rs
index e850508d657..a226f91b5a8 100644
--- a/components/script/dom/htmltextareaelement.rs
+++ b/components/script/dom/htmltextareaelement.rs
@@ -73,8 +73,7 @@ impl LayoutHTMLTextAreaElementHelpers for LayoutJS<HTMLTextAreaElement> {
         unsafe {
             (*self.upcast::<Element>().unsafe_get())
                 .get_attr_for_layout(&ns!(), &atom!("cols"))
-                .map(AttrValue::as_uint)
-                .unwrap_or(DEFAULT_COLS)
+                .map_or(DEFAULT_COLS, AttrValue::as_uint)
         }
     }
 
@@ -83,8 +82,7 @@ impl LayoutHTMLTextAreaElementHelpers for LayoutJS<HTMLTextAreaElement> {
         unsafe {
             (*self.upcast::<Element>().unsafe_get())
                 .get_attr_for_layout(&ns!(), &atom!("rows"))
-                .map(AttrValue::as_uint)
-                .unwrap_or(DEFAULT_ROWS)
+                .map_or(DEFAULT_ROWS, AttrValue::as_uint)
         }
     }
 }
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index ee82a25733f..021d595fbf8 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -768,7 +768,7 @@ impl Node {
         NodeInfo {
             uniqueId: self.get_unique_id(),
             baseURI: String::from(self.BaseURI()),
-            parent: self.GetParentNode().map(|node| node.get_unique_id()).unwrap_or("".to_owned()),
+            parent: self.GetParentNode().map_or("".to_owned(), |node| node.get_unique_id()),
             nodeType: self.NodeType(),
             namespaceURI: String::new(), //FIXME
             nodeName: String::from(self.NodeName()),
@@ -783,8 +783,7 @@ impl Node {
             isDocumentElement:
                 self.owner_doc()
                     .GetDocumentElement()
-                    .map(|elem| elem.upcast::<Node>() == self)
-                    .unwrap_or(false),
+                    .map_or(false, |elem| elem.upcast::<Node>() == self),
 
             shortValue: self.GetNodeValue().map(String::from).unwrap_or_default(), //FIXME: truncate
             incompleteValue: false, //FIXME: reflect truncation
@@ -1602,9 +1601,10 @@ impl Node {
             },
             NodeTypeId::Document(_) => {
                 let document = node.downcast::<Document>().unwrap();
-                let is_html_doc = match document.is_html_document() {
-                    true => IsHTMLDocument::HTMLDocument,
-                    false => IsHTMLDocument::NonHTMLDocument,
+                let is_html_doc = if document.is_html_document() {
+                    IsHTMLDocument::HTMLDocument
+                } else {
+                    IsHTMLDocument::NonHTMLDocument
                 };
                 let window = document.window();
                 let loader = DocumentLoader::new(&*document.loader());
@@ -2435,8 +2435,7 @@ impl<'a> UnbindContext<'a> {
         if let Some(index) = self.index.get() {
             return index;
         }
-        let index =
-            self.prev_sibling.map(|sibling| sibling.index() + 1).unwrap_or(0);
+        let index = self.prev_sibling.map_or(0, |sibling| sibling.index() + 1);
         self.index.set(Some(index));
         index
     }
diff --git a/components/script/dom/userscripts.rs b/components/script/dom/userscripts.rs
index 6cd08257b00..91f521c6922 100644
--- a/components/script/dom/userscripts.rs
+++ b/components/script/dom/userscripts.rs
@@ -31,7 +31,7 @@ pub fn load_script(head: &HTMLHeadElement) {
             PathBuf::from(path_str)
         };
 
-        let mut files = read_dir(&path).ok().expect("Bad path passed to --userscripts")
+        let mut files = read_dir(&path).expect("Bad path passed to --userscripts")
                                        .filter_map(|e| e.ok())
                                        .map(|e| e.path()).collect::<Vec<_>>();
 
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index c373fc7eb38..c47b9164a43 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -323,7 +323,7 @@ impl Window {
     }
 
     pub fn css_error_reporter(&self) -> Box<ParseErrorReporter + Send> {
-        return self.error_reporter.clone();
+        self.error_reporter.clone()
     }
 }
 
@@ -782,9 +782,7 @@ impl WindowMethods for Window {
 
     // https://drafts.csswg.org/cssom-view/#dom-window-devicepixelratio
     fn DevicePixelRatio(&self) -> Finite<f64> {
-        let dpr = self.window_size.get()
-                                  .map(|data| data.device_pixel_ratio.get())
-                                  .unwrap_or(1.0f32);
+        let dpr = self.window_size.get().map_or(1.0f32, |data| data.device_pixel_ratio.get());
         Finite::wrap(dpr as f64)
     }
 }
@@ -904,10 +902,10 @@ impl Window {
         let point = Point2D::new(x, y);
         let smooth = match behavior {
             ScrollBehavior::Auto => {
-                element.map(|_element| {
+                element.map_or(false, |_element| {
                     // TODO check computed scroll-behaviour CSS property
                     true
-                }).unwrap_or(false)
+                })
             }
             ScrollBehavior::Instant => false,
             ScrollBehavior::Smooth => true
diff --git a/components/script/dom/xmlhttprequest.rs b/components/script/dom/xmlhttprequest.rs
index 1ef5e361bf8..cac963c85d9 100644
--- a/components/script/dom/xmlhttprequest.rs
+++ b/components/script/dom/xmlhttprequest.rs
@@ -271,7 +271,7 @@ impl XMLHttpRequest {
         }
 
         let (action_sender, action_receiver) = ipc::channel().unwrap();
-        let listener = box NetworkListener {
+        let listener = NetworkListener {
             context: context,
             script_chan: script_chan,
         };
@@ -483,7 +483,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
             _ => data
         };
         let extracted = data.as_ref().map(|d| d.extract());
-        self.request_body_len.set(extracted.as_ref().map(|e| e.len()).unwrap_or(0));
+        self.request_body_len.set(extracted.as_ref().map_or(0, |e| e.len()));
 
         // Step 6
         self.upload_events.set(false);
@@ -1120,13 +1120,12 @@ impl XMLHttpRequest {
         let content_type = mime_type.map(|mime|{
             DOMString::from(format!("{}", mime))
         });
-        let document = Document::new(win,
-                                     parsed_url,
-                                     is_html_document,
-                                     content_type,
-                                     None,
-                                     DocumentSource::FromParser, docloader);
-       document
+        Document::new(win,
+                      parsed_url,
+                      is_html_document,
+                      content_type,
+                      None,
+                      DocumentSource::FromParser, docloader)
     }
 
     fn filter_response_headers(&self) -> Headers {
diff --git a/components/script/lib.rs b/components/script/lib.rs
index ff07264362e..71afdb02df4 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -130,7 +130,7 @@ fn perform_platform_specific_initialization() {
                         }
                     }
                 };
-                match libc::setrlimit(libc::RLIMIT_NOFILE, &mut rlim) {
+                match libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) {
                     0 => (),
                     _ => warn!("Failed to set file count limit"),
                 };
diff --git a/components/script/reporter.rs b/components/script/reporter.rs
index 1ad6ee9987e..9893cb12ebe 100644
--- a/components/script/reporter.rs
+++ b/components/script/reporter.rs
@@ -22,10 +22,9 @@ impl ParseErrorReporter for CSSErrorReporter {
      }
 
      fn clone(&self) -> Box<ParseErrorReporter + Send + Sync> {
-         let error_reporter = box CSSErrorReporter { pipelineid: self.pipelineid, } ;
-         return error_reporter;
+         box CSSErrorReporter { pipelineid: self.pipelineid, }
      }
      fn pipeline(&self) -> PipelineId {
-         return self.pipelineid;
+         self.pipelineid
      }
 }
diff --git a/components/script/script_task.rs b/components/script/script_task.rs
index 68ef6a2a474..6d9b2bee301 100644
--- a/components/script/script_task.rs
+++ b/components/script/script_task.rs
@@ -1948,13 +1948,11 @@ impl ScriptTask {
 
                 // Notify Constellation about anchors that are no longer mouse over targets.
                 for target in &*prev_mouse_over_targets {
-                    if !mouse_over_targets.contains(target) {
-                        if target.is::<HTMLAnchorElement>() {
-                            let event = ConstellationMsg::NodeStatus(None);
-                            let ConstellationChan(ref chan) = self.constellation_chan;
-                            chan.send(event).unwrap();
-                            break;
-                        }
+                    if !mouse_over_targets.contains(target) && target.is::<HTMLAnchorElement>() {
+                        let event = ConstellationMsg::NodeStatus(None);
+                        let ConstellationChan(ref chan) = self.constellation_chan;
+                        chan.send(event).unwrap();
+                        break;
                     }
                 }
 
@@ -2108,7 +2106,7 @@ impl ScriptTask {
         let context = Arc::new(Mutex::new(ParserContext::new(id, subpage, script_chan.clone(),
                                                              load_data.url.clone())));
         let (action_sender, action_receiver) = ipc::channel().unwrap();
-        let listener = box NetworkListener {
+        let listener = NetworkListener {
             context: context,
             script_chan: script_chan.clone(),
         };
diff --git a/components/script/webdriver_handlers.rs b/components/script/webdriver_handlers.rs
index bd5fd9576c7..2ae4931937d 100644
--- a/components/script/webdriver_handlers.rs
+++ b/components/script/webdriver_handlers.rs
@@ -191,7 +191,7 @@ pub fn handle_get_text(page: &Rc<Page>,
                        reply: IpcSender<Result<String, ()>>) {
     reply.send(match find_node_by_unique_id(&*page, pipeline, node_id) {
         Some(ref node) => {
-            Ok(node.GetTextContent().map(String::from).unwrap_or("".to_owned()))
+            Ok(node.GetTextContent().map_or("".to_owned(), String::from))
         },
         None => Err(())
     }).unwrap();
diff --git a/components/style/restyle_hints.rs b/components/style/restyle_hints.rs
index f15685ff137..e1b1b477201 100644
--- a/components/style/restyle_hints.rs
+++ b/components/style/restyle_hints.rs
@@ -112,27 +112,27 @@ impl<'a, E> Element for ElementWrapper<'a, E> where E: Element {
     state_pseudo_classes!(snapshot_state_accessors);
 
     fn parent_element(&self) -> Option<Self> {
-        self.element.parent_element().map(|el| ElementWrapper::new(el))
+        self.element.parent_element().map(ElementWrapper::new)
     }
     fn first_child_element(&self) -> Option<Self> {
-        self.element.first_child_element().map(|el| ElementWrapper::new(el))
+        self.element.first_child_element().map(ElementWrapper::new)
     }
     fn last_child_element(&self) -> Option<Self> {
-        self.element.last_child_element().map(|el| ElementWrapper::new(el))
+        self.element.last_child_element().map(ElementWrapper::new)
     }
     fn prev_sibling_element(&self) -> Option<Self> {
-        self.element.prev_sibling_element().map(|el| ElementWrapper::new(el))
+        self.element.prev_sibling_element().map(ElementWrapper::new)
     }
     fn next_sibling_element(&self) -> Option<Self> {
-        self.element.next_sibling_element().map(|el| ElementWrapper::new(el))
+        self.element.next_sibling_element().map(ElementWrapper::new)
     }
     fn is_html_element_in_html_document(&self) -> bool {
         self.element.is_html_element_in_html_document()
     }
-    fn get_local_name<'b>(&'b self) -> &'b Atom {
+    fn get_local_name(&self) -> &Atom {
         self.element.get_local_name()
     }
-    fn get_namespace<'b>(&'b self) -> &'b Namespace {
+    fn get_namespace<'b>(&self) -> &Namespace {
         self.element.get_namespace()
     }
     fn get_id(&self) -> Option<Atom> {
diff --git a/components/style/selector_matching.rs b/components/style/selector_matching.rs
index b5bde84a38d..1f3f187027b 100644
--- a/components/style/selector_matching.rs
+++ b/components/style/selector_matching.rs
@@ -47,7 +47,7 @@ impl ParseErrorReporter for StdoutErrorReporter {
     }
 
     fn pipeline(&self) -> PipelineId {
-       return PipelineId::fake_root_pipeline_id();
+       PipelineId::fake_root_pipeline_id()
      }
 }
 
@@ -129,7 +129,7 @@ pub struct Stylist {
 impl Stylist {
     #[inline]
     pub fn new(device: Device) -> Stylist {
-        let stylist = Stylist {
+        Stylist {
             viewport_constraints: None,
             device: device,
             is_device_dirty: true,
@@ -140,9 +140,8 @@ impl Stylist {
             after_map: PerPseudoElementSelectorMap::new(),
             rules_source_order: 0,
             state_deps: DependencySet::new(),
-        };
+        }
         // FIXME: Add iso-8859-9.css when the document’s encoding is ISO-8859-8.
-        stylist
     }
 
     pub fn update(&mut self, doc_stylesheets: &[Arc<Stylesheet>],
diff --git a/components/style/stylesheets.rs b/components/style/stylesheets.rs
index 8da4bc5e94a..a2efb95e80e 100644
--- a/components/style/stylesheets.rs
+++ b/components/style/stylesheets.rs
@@ -201,19 +201,16 @@ impl<'a> Iterator for Rules<'a> {
             let top = self.stack.len() - 1;
             while let Some(rule) = self.stack[top].next() {
                 // handle conditional group rules
-                match rule {
-                    &CSSRule::Media(ref rule) => {
-                        if let Some(device) = self.device {
-                            if rule.evaluate(device) {
-                                self.stack.push(rule.rules.iter());
-                            } else {
-                                continue
-                            }
-                        } else {
+                if let &CSSRule::Media(ref rule) = rule {
+                    if let Some(device) = self.device {
+                        if rule.evaluate(device) {
                             self.stack.push(rule.rules.iter());
+                        } else {
+                            continue
                         }
+                    } else {
+                        self.stack.push(rule.rules.iter());
                     }
-                    _ => {}
                 }
 
                 return Some(rule)
diff --git a/components/util/opts.rs b/components/util/opts.rs
index 0b276e644e1..0967dc59692 100644
--- a/components/util/opts.rs
+++ b/components/util/opts.rs
@@ -581,11 +581,10 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
     let is_running_problem_test =
         url_opt
         .as_ref()
-        .map(|url|
+        .map_or(false, |url|
              url.starts_with("http://web-platform.test:8000/2dcontext/drawing-images-to-the-canvas/") ||
              url.starts_with("http://web-platform.test:8000/_mozilla/mozilla/canvas/") ||
-             url.starts_with("http://web-platform.test:8000/_mozilla/css/canvas_over_area.html"))
-        .unwrap_or(false);
+             url.starts_with("http://web-platform.test:8000/_mozilla/css/canvas_over_area.html"));
 
     let url = match url_opt {
         Some(url_string) => {
diff --git a/components/util/prefs.rs b/components/util/prefs.rs
index b73bf9158d9..0d6a4c94660 100644
--- a/components/util/prefs.rs
+++ b/components/util/prefs.rs
@@ -146,7 +146,7 @@ fn read_prefs() -> Result<HashMap<String, Pref>, ()> {
 }
 
 pub fn get_pref(name: &str) -> Arc<PrefValue> {
-    PREFS.lock().unwrap().get(name).map(|x| x.value().clone()).unwrap_or(Arc::new(PrefValue::Missing))
+    PREFS.lock().unwrap().get(name).map_or(Arc::new(PrefValue::Missing), |x| x.value().clone())
 }
 
 pub fn set_pref(name: &str, value: PrefValue) {
diff --git a/components/util/resource_files.rs b/components/util/resource_files.rs
index cd7363f9c4c..67ae9f6550a 100644
--- a/components/util/resource_files.rs
+++ b/components/util/resource_files.rs
@@ -33,7 +33,7 @@ pub fn resources_dir_path() -> PathBuf {
             // FIXME: Find a way to not rely on the executable being
             // under `<servo source>[/$target_triple]/target/debug`
             // or `<servo source>[/$target_triple]/target/release`.
-            let mut path = env::current_exe().ok().expect("can't get exe path");
+            let mut path = env::current_exe().expect("can't get exe path");
             path.pop();
             path.push("resources");
             if !path.is_dir() {   // resources dir not in same dir as exe?
diff --git a/components/util/str.rs b/components/util/str.rs
index f00dd8e3ea7..fdcdcb8877a 100644
--- a/components/util/str.rs
+++ b/components/util/str.rs
@@ -461,19 +461,17 @@ pub fn parse_legacy_color(mut input: &str) -> Result<RGBA, ()> {
 
     // Step 6.
     if input.len() == 4 {
-        match (input.as_bytes()[0],
-               hex(input.as_bytes()[1] as char),
-               hex(input.as_bytes()[2] as char),
-               hex(input.as_bytes()[3] as char)) {
-            (b'#', Ok(r), Ok(g), Ok(b)) => {
-                return Ok(RGBA {
-                    red: (r as f32) * 17.0 / 255.0,
-                    green: (g as f32) * 17.0 / 255.0,
-                    blue: (b as f32) * 17.0 / 255.0,
-                    alpha: 1.0,
-                })
-            }
-            _ => {}
+        if let (b'#', Ok(r), Ok(g), Ok(b)) =
+                (input.as_bytes()[0],
+                hex(input.as_bytes()[1] as char),
+                hex(input.as_bytes()[2] as char),
+                hex(input.as_bytes()[3] as char)) {
+            return Ok(RGBA {
+                red: (r as f32) * 17.0 / 255.0,
+                green: (g as f32) * 17.0 / 255.0,
+                blue: (b as f32) * 17.0 / 255.0,
+                alpha: 1.0,
+            })
         }
     }