It's calling HTMLElement::directionalityIfDirIsAuto here but this function may sometime return a nullopt: https://searchfox.org/wubkat/rev/cf0cfbaf1ad7728a145c06e3539170870bbb913f/Source/WebCore/html/HTMLTextFormControlElement.cpp#825
Pull request: https://github.com/WebKit/WebKit/pull/4741
Committed 254943@main (3c75189741bc): <https://commits.webkit.org/254943@main> Reviewed commits have been landed. Closing PR #4741 and removing active labels.
<rdar://problem/100490959>