To reuse the existing CSS Selector JIT Compiler, we should translate any nested selector rule to the equivalent flat (=non nested) one via the pseudo class :is()
Part of the more general css-nesting-1 bug 223497
Pull request: https://github.com/WebKit/WebKit/pull/8051
Committed 258367@main (8972793414d9): <https://commits.webkit.org/258367@main>
Reviewed commits have been landed. Closing PR #8051 and removing active labels.