Foat clear pushes the block level box either below the floats, or just one side below but the other side could overlap.
<rdar://problem/59918356>
Created attachment 392058 [details] Patch
Comment on attachment 392058 [details] Patch Clearing flags on attachment: 392058 Committed r257682: <https://trac.webkit.org/changeset/257682>
All reviewed patches have been landed. Closing bug.