This issue was showing up as unchecked exception errors when running the JSC stress tests.
Pull request: https://github.com/WebKit/WebKit/pull/2854
Committed 252954@main (6a7774646654): <https://commits.webkit.org/252954@main> Reviewed commits have been landed. Closing PR #2854 and removing active labels.
<rdar://problem/97793325>