Backport "Nowarn extension matching nonpublic member" to 3.6#22276

WojciechMazur merged 2 commits intobackport-release-3.6.3-22185scala/scala3:backport-release-3.6.3-22185from

backport-release-3.6.3-21825scala/scala3:backport-release-3.6.3-21825Copy head branch name to clipboard