Fix warnings introduced in newer Rust Nightly

This does not (yet) upgrade ./rust-toolchain

The warnings:

* dead_code "field is never read"
* redundant_semicolons "unnecessary trailing semicolon"
* non_fmt_panic "panic message is not a string literal, this is no longer accepted in Rust 2021"
* unstable_name_collisions "a method with this name may be added to the standard library in the future"
* legacy_derive_helpers "derive helper attribute is used before it is introduced" rust-lang/rust#79202

components/compositing/build.rs

@@ -47,6 +47,6 @@ fn main() {
                 _ => panic!("Cannot find package definitions in lockfile"),
             }
         },
-        Err(e) => panic!(e),
+        Err(e) => panic!("{}", e),
     }
 }

components/compositing/compositor.rs

@@ -142,6 +142,7 @@ pub struct IOCompositor<Window: WindowMethods + ?Sized> {
     pub shutdown_state: ShutdownState,
 
     /// Tracks the last composite time.
+    #[allow(dead_code)] // FIXME: do something with this or remove it
     last_composite_time: u64,
 
     /// Tracks whether the zoom action has happened recently.

components/config/pref_util.rs

@@ -113,12 +113,7 @@ macro_rules! impl_from_pref {
                     if let $variant(value) = other {
                         value.into()
                     } else {
-                        panic!(
-                            format!("Cannot convert {:?} to {:?}",
-                                other,
-                                std::any::type_name::<$t>()
-                            )
-                        );
+                        panic!("Cannot convert {:?} to {:?}", other, std::any::type_name::<$t>())
                     }
                 }
             }

components/config_plugins/lib.rs

@@ -132,12 +132,14 @@ impl Build {
             .get_field_name_mapping()
             .map(|pref_attr| pref_attr.value())
             .unwrap_or_else(|| {
-                path_stack
-                    .iter()
-                    .chain(iter::once(&field.name))
-                    .map(Ident::to_string)
-                    .intersperse(String::from("."))
-                    .collect()
+                Itertools::intersperse(
+                    path_stack
+                        .iter()
+                        .chain(iter::once(&field.name))
+                        .map(Ident::to_string),
+                    String::from("."),
+                )
+                .collect()
             })
     }
 

components/devtools/actors/framerate.rs

@@ -17,7 +17,10 @@ pub struct FramerateActor {
     name: String,
     pipeline: PipelineId,
     script_sender: IpcSender<DevtoolScriptControlMsg>,
+
+    #[allow(dead_code)] // FIXME: do something with this or remove it
     start_time: Option<u64>,
+
     is_recording: bool,
     ticks: Vec<HighResolutionStamp>,
 }

components/layout/table_wrapper.rs

@@ -822,6 +822,8 @@ impl ExcessInlineSizeDistributionInfo {
 /// An intermediate column size assignment.
 struct IntermediateColumnInlineSize {
     size: Au,
+
+    #[allow(dead_code)] // FIXME: do something with this or remove it
     percentage: f32,
 }
 

components/layout_thread/lib.rs

@@ -190,6 +190,7 @@ pub struct LayoutThread {
     root_flow: RefCell<Option<FlowRef>>,
 
     /// The document-specific shared lock used for author-origin stylesheets
+    #[allow(dead_code)] // FIXME: do something with this or remove it
     document_shared_lock: Option<SharedRwLock>,
 
     /// A counter for epoch messages

components/layout_thread_2020/lib.rs

@@ -168,6 +168,7 @@ pub struct LayoutThread {
     fragment_tree: RefCell<Option<Arc<FragmentTree>>>,
 
     /// The document-specific shared lock used for author-origin stylesheets
+    #[allow(dead_code)] // FIXME: do something with this or remove it
     document_shared_lock: Option<SharedRwLock>,
 
     /// A counter for epoch messages

components/net/tests/data_loader.rs

@@ -44,7 +44,7 @@ fn assert_parse(
                     filtered: FilteredMetadata::Basic(m),
                     ..
                 }) => m,
-                result => panic!(result),
+                result => panic!("{:?}", result),
             };
             assert_eq!(metadata.content_type.map(Serde::into_inner), content_type);
             assert_eq!(metadata.charset.as_ref().map(String::deref), charset);

components/net_traits/response.rs

@@ -312,7 +312,7 @@ impl Response {
             metadata.referrer_policy = response.referrer_policy.clone();
             metadata.redirected = response.actual_response().url_list.len() > 1;
             metadata
-        };
+        }
 
         if let Some(error) = self.get_network_error() {
             return Err(error.clone());

components/profile/mem.rs

@@ -101,18 +101,15 @@ impl Profiler {
                 let name_clone = name.clone();
                 match self.reporters.insert(name, reporter) {
                     None => true,
-                    Some(_) => panic!(format!(
-                        "RegisterReporter: '{}' name is already in use",
-                        name_clone
-                    )),
+                    Some(_) => panic!("RegisterReporter: '{}' name is already in use", name_clone),
                 }
             },
 
             ProfilerMsg::UnregisterReporter(name) => {
                 // Panic if it hasn't previously been registered.
                 match self.reporters.remove(&name) {
                     Some(_) => true,
-                    None => panic!(format!("UnregisterReporter: '{}' name is unknown", &name)),
+                    None => panic!("UnregisterReporter: '{}' name is unknown", &name),
                 }
             },
 

components/style/gecko/url.rs

@@ -21,8 +21,8 @@ use style_traits::{CssWriter, ParseError, ToCss};
 use to_shmem::{self, SharedMemoryBuilder, ToShmem};
 
 /// A CSS url() value for gecko.
-#[css(function = "url")]
 #[derive(Clone, Debug, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
+#[css(function = "url")]
 #[repr(C)]
 pub struct CssUrl(pub Arc<CssUrlData>);
 

components/style/media_queries/media_list.rs

@@ -14,8 +14,8 @@ use cssparser::{Delimiter, Parser};
 use cssparser::{ParserInput, Token};
 
 /// A type that encapsulates a media query list.
-#[css(comma, derive_debug)]
 #[derive(Clone, MallocSizeOf, ToCss, ToShmem)]
+#[css(comma, derive_debug)]
 pub struct MediaList {
     /// The list of media queries.
     #[css(iterable)]

components/style/properties/helpers.mako.rs

@@ -170,9 +170,6 @@
             /// Making this type generic allows the compiler to figure out the
             /// animated value for us, instead of having to implement it
             /// manually for every type we care about.
-            % if separator == "Comma":
-            #[css(comma)]
-            % endif
             #[derive(
                 Clone,
                 Debug,
@@ -182,6 +179,9 @@
                 ToResolvedValue,
                 ToCss,
             )]
+            % if separator == "Comma":
+            #[css(comma)]
+            % endif
             pub struct OwnedList<T>(
                 % if not allow_empty:
                 #[css(iterable)]
@@ -198,16 +198,16 @@
             % else:
             pub use self::ComputedList as List;
 
-            % if separator == "Comma":
-            #[css(comma)]
-            % endif
             #[derive(
                 Clone,
                 Debug,
                 MallocSizeOf,
                 PartialEq,
                 ToCss,
             )]
+            % if separator == "Comma":
+            #[css(comma)]
+            % endif
             pub struct ComputedList(
                 % if not allow_empty:
                 #[css(iterable)]
@@ -324,10 +324,10 @@
         }
 
         /// The specified value of ${name}.
+        #[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
         % if separator == "Comma":
         #[css(comma)]
         % endif
-        #[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
         pub struct SpecifiedValue(
             % if not allow_empty:
             #[css(iterable)]

components/style/stylesheets/document_rule.rs

@@ -215,8 +215,8 @@ impl DocumentMatchingFunction {
 /// The `@document` rule's condition is written as a comma-separated list of
 /// URL matching functions, and the condition evaluates to true whenever any
 /// one of those functions evaluates to true.
-#[css(comma)]
 #[derive(Clone, Debug, ToCss, ToShmem)]
+#[css(comma)]
 pub struct DocumentCondition(#[css(iterable)] Vec<DocumentMatchingFunction>);
 
 impl DocumentCondition {

components/style/stylesheets/keyframes_rule.rs

@@ -149,8 +149,8 @@ impl KeyframePercentage {
 
 /// A keyframes selector is a list of percentages or from/to symbols, which are
 /// converted at parse time to percentages.
-#[css(comma)]
 #[derive(Clone, Debug, Eq, PartialEq, ToCss, ToShmem)]
+#[css(comma)]
 pub struct KeyframeSelector(#[css(iterable)] Vec<KeyframePercentage>);
 
 impl KeyframeSelector {

components/style/values/animated/font.rs

@@ -116,7 +116,7 @@ impl<'a> FontSettingTagIter<'a> {
             let mut sorted_tags = Vec::from_iter(tags.iter());
             sorted_tags.sort_by_key(|k| k.tag.0);
             sorted_tags
-        };
+        }
 
         Ok(FontSettingTagIter {
             a_state: FontSettingTagIterState::new(as_new_sorted_tags(&a_settings.0)),

components/style/values/generics/basic_shape.rs

@@ -91,7 +91,6 @@ impl Default for ShapeBox {
 
 /// A value for the `clip-path` property.
 #[allow(missing_docs)]
-#[animation(no_bound(U))]
 #[derive(
     Animate,
     Clone,
@@ -106,6 +105,7 @@ impl Default for ShapeBox {
     ToResolvedValue,
     ToShmem,
 )]
+#[animation(no_bound(U))]
 #[repr(u8)]
 pub enum GenericClipPath<BasicShape, U> {
     #[animation(error)]
@@ -126,7 +126,6 @@ pub use self::GenericClipPath as ClipPath;
 
 /// A value for the `shape-outside` property.
 #[allow(missing_docs)]
-#[animation(no_bound(I))]
 #[derive(
     Animate,
     Clone,
@@ -141,6 +140,7 @@ pub use self::GenericClipPath as ClipPath;
     ToResolvedValue,
     ToShmem,
 )]
+#[animation(no_bound(I))]
 #[repr(u8)]
 pub enum GenericShapeOutside<BasicShape, I> {
     #[animation(error)]
@@ -193,7 +193,6 @@ pub use self::GenericBasicShape as BasicShape;
 
 /// <https://drafts.csswg.org/css-shapes/#funcdef-inset>
 #[allow(missing_docs)]
-#[css(function = "inset")]
 #[derive(
     Animate,
     Clone,
@@ -207,6 +206,7 @@ pub use self::GenericBasicShape as BasicShape;
     ToResolvedValue,
     ToShmem,
 )]
+#[css(function = "inset")]
 #[repr(C)]
 pub struct InsetRect<LengthPercentage, NonNegativeLengthPercentage> {
     pub rect: Rect<LengthPercentage>,
@@ -216,7 +216,6 @@ pub struct InsetRect<LengthPercentage, NonNegativeLengthPercentage> {
 
 /// <https://drafts.csswg.org/css-shapes/#funcdef-circle>
 #[allow(missing_docs)]
-#[css(function)]
 #[derive(
     Animate,
     Clone,
@@ -231,6 +230,7 @@ pub struct InsetRect<LengthPercentage, NonNegativeLengthPercentage> {
     ToResolvedValue,
     ToShmem,
 )]
+#[css(function)]
 #[repr(C)]
 pub struct Circle<H, V, NonNegativeLengthPercentage> {
     pub position: GenericPosition<H, V>,
@@ -239,7 +239,6 @@ pub struct Circle<H, V, NonNegativeLengthPercentage> {
 
 /// <https://drafts.csswg.org/css-shapes/#funcdef-ellipse>
 #[allow(missing_docs)]
-#[css(function)]
 #[derive(
     Animate,
     Clone,
@@ -254,6 +253,7 @@ pub struct Circle<H, V, NonNegativeLengthPercentage> {
     ToResolvedValue,
     ToShmem,
 )]
+#[css(function)]
 #[repr(C)]
 pub struct Ellipse<H, V, NonNegativeLengthPercentage> {
     pub position: GenericPosition<H, V>,
@@ -293,7 +293,6 @@ pub use self::GenericShapeRadius as ShapeRadius;
 /// A generic type for representing the `polygon()` function
 ///
 /// <https://drafts.csswg.org/css-shapes/#funcdef-polygon>
-#[css(comma, function = "polygon")]
 #[derive(
     Clone,
     Debug,
@@ -306,6 +305,7 @@ pub use self::GenericShapeRadius as ShapeRadius;
     ToResolvedValue,
     ToShmem,
 )]
+#[css(comma, function = "polygon")]
 #[repr(C)]
 pub struct GenericPolygon<LengthPercentage> {
     /// The filling rule for a polygon.
@@ -364,7 +364,6 @@ pub enum FillRule {
 /// The path function defined in css-shape-2.
 ///
 /// https://drafts.csswg.org/css-shapes-2/#funcdef-path
-#[css(comma)]
 #[derive(
     Animate,
     Clone,
@@ -379,6 +378,7 @@ pub enum FillRule {
     ToResolvedValue,
     ToShmem,
 )]
+#[css(comma)]
 #[repr(C)]
 pub struct Path {
     /// The filling rule for the svg path.

components/style/values/generics/effects.rs

@@ -35,7 +35,6 @@ pub use self::GenericBoxShadow as BoxShadow;
 
 /// A generic value for a single `filter`.
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
-#[animation(no_bound(U))]
 #[derive(
     Clone,
     ComputeSquaredDistance,
@@ -49,6 +48,7 @@ pub use self::GenericBoxShadow as BoxShadow;
     ToResolvedValue,
     ToShmem,
 )]
+#[animation(no_bound(U))]
 #[repr(C, u8)]
 pub enum GenericFilter<Angle, NonNegativeFactor, ZeroToOneFactor, Length, Shadow, U> {
     /// `blur(<length>)`

components/style/values/generics/font.rs

@@ -77,7 +77,6 @@ pub struct VariationValue<Number> {
 }
 
 /// A value both for font-variation-settings and font-feature-settings.
-#[css(comma)]
 #[derive(
     Clone,
     Debug,
@@ -90,6 +89,7 @@ pub struct VariationValue<Number> {
     ToResolvedValue,
     ToShmem,
 )]
+#[css(comma)]
 pub struct FontSettings<T>(#[css(if_empty = "normal", iterable)] pub Box<[T]>);
 
 impl<T> FontSettings<T> {

components/style/values/generics/image.rs

@@ -264,7 +264,6 @@ impl ToCss for PaintWorklet {
 ///
 /// `-moz-image-rect(<uri>, top, right, bottom, left);`
 #[allow(missing_docs)]
-#[css(comma, function = "-moz-image-rect")]
 #[derive(
     Clone,
     Debug,
@@ -276,6 +275,7 @@ impl ToCss for PaintWorklet {
     ToResolvedValue,
     ToShmem,
 )]
+#[css(comma, function = "-moz-image-rect")]
 #[repr(C)]
 pub struct GenericMozImageRect<NumberOrPercentage, MozImageRectUrl> {
     pub url: MozImageRectUrl,