Add support for ::highlight

scripts/build-prefixes.js

@@ -292,6 +292,7 @@ let mdnFeatures = {
   oklabColors: mdn.css.types.color.oklab.__compat.support,
   colorFunction: mdn.css.types.color.color.__compat.support,
   spaceSeparatedColorNotation: mdn.css.types.color.rgb.space_separated_parameters.__compat.support,
+  highlight: mdn.css.selectors.highlight.__compat.support,
   textDecorationThicknessPercent: mdn.css.properties['text-decoration-thickness'].percentage.__compat.support,
   textDecorationThicknessShorthand: mdn.css.properties['text-decoration'].includes_thickness.__compat.support,
   cue: mdn.css.selectors.cue.__compat.support,

selectors/parser.rs

@@ -3933,6 +3933,10 @@ pub mod tests {
     assert!(parse("foo::details-content").is_ok());
     assert!(parse("foo::target-text").is_ok());
 
+    assert!(parse("::highlight").is_err());
+    assert!(parse("::highlight()").is_err());
+    assert!(parse("::highlight(custom-highlight-name)").is_ok());
+
     assert!(parse("select::picker").is_err());
     assert!(parse("::picker()").is_err());
     assert!(parse("::picker(select)").is_ok());

src/compat.rs

@@ -93,6 +93,7 @@ pub enum Feature {
   HasSelector,
   HebrewListStyleType,
   HexAlphaColors,
+  Highlight,
   HiraganaIrohaListStyleType,
   HiraganaListStyleType,
   HypotFunction,
@@ -2455,6 +2456,51 @@ impl Feature {
           return false;
         }
       }
+      Feature::Highlight => {
+        if let Some(version) = browsers.chrome {
+          if version < 6881280 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.edge {
+          if version < 6881280 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.firefox {
+          if version < 9175040 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.opera {
+          if version < 4718592 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.safari {
+          if version < 1114624 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.ios_saf {
+          if version < 1114624 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.samsung {
+          if version < 1310720 {
+            return false;
+          }
+        }
+        if let Some(version) = browsers.android {
+          if version < 6881280 {
+            return false;
+          }
+        }
+        if browsers.ie.is_some() {
+          return false;
+        }
+      }
       Feature::TextDecorationThicknessPercent => {
         if let Some(version) = browsers.chrome {
           if version < 5701632 {

src/selector.rs

@@ -320,6 +320,7 @@ impl<'a, 'o, 'i> parcel_selectors::parser::Parser<'i> for SelectorParser<'a, 'o,
     let pseudo_element = match_ignore_ascii_case! { &name,
       "cue" => CueFunction { selector: Box::new(Selector::parse(self, arguments)?) },
       "cue-region" => CueRegionFunction { selector: Box::new(Selector::parse(self, arguments)?) },
+      "highlight" => HighlightFunction { name: CustomIdent::parse(arguments)? },
       "picker" => PickerFunction { identifier: Ident::parse(arguments)? },
       "view-transition-group" => ViewTransitionGroup { part: ViewTransitionPartSelector::parse(arguments)? },
       "view-transition-image-pair" => ViewTransitionImagePair { part: ViewTransitionPartSelector::parse(arguments)? },
@@ -906,6 +907,11 @@ pub enum PseudoElement<'i> {
   /// The [::placeholder](https://drafts.csswg.org/css-pseudo-4/#placeholder-pseudo) pseudo element.
   #[cfg_attr(feature = "serde", serde(with = "PrefixWrapper"))]
   Placeholder(VendorPrefix),
+  /// The [::highlight()](https://drafts.csswg.org/css-highlight-api/#custom-highlight-pseudo) functional pseudo element.
+  HighlightFunction {
+    /// A custom highlight name.
+    name: CustomIdent<'i>,
+  },
   ///  The [::marker](https://drafts.csswg.org/css-pseudo-4/#marker-pseudo) pseudo element.
   Marker,
   /// The [::backdrop](https://fullscreen.spec.whatwg.org/#::backdrop-pseudo-element) pseudo element.
@@ -1167,6 +1173,11 @@ where
     FirstLetter => dest.write_str(":first-letter"),
     DetailsContent => dest.write_str("::details-content"),
     TargetText => dest.write_str("::target-text"),
+    HighlightFunction { name } => {
+      dest.write_str("::highlight(")?;
+      name.to_css(dest)?;
+      dest.write_char(')')
+    }
     Marker => dest.write_str("::marker"),
     Selection(prefix) => write_prefixed!(prefix, "selection"),
     Cue => dest.write_str("::cue"),
@@ -1944,6 +1955,7 @@ pub(crate) fn is_compatible(selectors: &[Selector], targets: Targets) -> bool {
           PseudoElement::TargetText => Feature::TargetText,
           PseudoElement::Selection(prefix) if *prefix == VendorPrefix::None => Feature::Selection,
           PseudoElement::Placeholder(prefix) if *prefix == VendorPrefix::None => Feature::Placeholder,
+          PseudoElement::HighlightFunction { name: _ } => Feature::Highlight,
           PseudoElement::Marker => Feature::MarkerPseudo,
           PseudoElement::Backdrop(prefix) if *prefix == VendorPrefix::None => Feature::Dialog,
           PseudoElement::Cue => Feature::Cue,