Auto merge of #16752 - jdm:css-parse-error, r=SimonSapin

Report more informative CSS errors

This requires https://github.com/servo/rust-cssparser/pull/143 for the final commit. There's no better way to split that work up, unfortunately, and it's extremely easy to bitrot. I would appreciate if we could expedite reviewing this work.

This is the work necessary to enable https://bugzilla.mozilla.org/show_bug.cgi?id=1352669. It makes sense to merge it separately because it's so much effort to keep it up to date with the ongoing Stylo work.

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes

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1 files changed, 2 insertions, 2 deletions

diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 189410ce77a..b4e7be3203a 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -2061,7 +2061,7 @@ impl ElementMethods for Element {
     // https://dom.spec.whatwg.org/#dom-element-matches
     fn Matches(&self, selectors: DOMString) -> Fallible<bool> {
         match SelectorParser::parse_author_origin_no_namespace(&selectors) {
-            Err(()) => Err(Error::Syntax),
+            Err(_) => Err(Error::Syntax),
             Ok(selectors) => {
                 let mut ctx = MatchingContext::new(MatchingMode::Normal, None);
                 Ok(matches_selector_list(&selectors, &Root::from_ref(self), &mut ctx))
@@ -2077,7 +2077,7 @@ impl ElementMethods for Element {
     // https://dom.spec.whatwg.org/#dom-element-closest
     fn Closest(&self, selectors: DOMString) -> Fallible<Option<Root<Element>>> {
         match SelectorParser::parse_author_origin_no_namespace(&selectors) {
-            Err(()) => Err(Error::Syntax),
+            Err(_) => Err(Error::Syntax),
             Ok(selectors) => {
                 let root = self.upcast::<Node>();
                 for element in root.inclusive_ancestors() {