Unless there are specific known issues, I think it may be a good idea to unmask samba-4.6 now. This series has been masked for testing for over 22 months, and in fact the next series 4.7 is now in RC. Time to update the mask to >=4.7.0_rc1? Thanks!
Have you please tested version 4.6?
I have tested it here, yes. By 22 months, if it hasn't seen some wider testing from this "masked for testing" plan, then it will never see any testing.
https://github.com/gentoo/gentoo/commit/99c0cddfe03f90efc08ea93bd7d5f39fd6d39068