Spec: https://drafts.csswg.org/selectors-4/#matches Default namespace declarations do not affect the compound selector representing the subject of any selector within a :is() or :not() pseudo-class, unless that compound selector contains an explicit universal selector or type selector. There are two WPT tests failing on WebKit due to this: * https://wpt.fyi/results/css/selectors/is-default-ns-002.html * https://wpt.fyi/results/css/selectors/not-default-ns-002.html
This has been fixed in Chromium in the following commits: * https://chromium-review.googlesource.com/c/chromium/src/+/2489891 * https://chromium-review.googlesource.com/c/chromium/src/+/2489647
Created attachment 416427 [details] Patch
Committed r270955: <https://trac.webkit.org/changeset/270955> All reviewed patches have been landed. Closing bug and clearing flags on attachment 416427 [details].
<rdar://problem/72443424>