Dom crashes if you visit AstComments field of Qmlfile. The root cause is invalidated CommentedElement data of the AstComment class. When the visitor is visiting CommentedElement::iterateDirectSubpaths, the visited element's m_preComment and m_postComment are invalid if the current owner type is AstComments.

Workaround is to get the valid m_preComment and m_postComment from AstComment by explicit casting, see the fix for QTBUG-123547.

Investigate why CommentedElement is invalidated, when you revert the fix for QTBUG-123547.