It is one of 3 places left in the parser that use backtrackingScope, and it is by far the simplest to remove.
Created attachment 372277 [details] Patch
Comment on attachment 372277 [details] Patch Clearing flags on attachment: 372277 Committed r246520: <https://trac.webkit.org/changeset/246520>
All reviewed patches have been landed. Closing bug.
<rdar://problem/51825612>