These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.61 s (backtrack: 0/20).

[ebuild  N     ] acct-group/smtpq-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-group/smtpd-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/smtpd-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/smtpq-0-r3::gentoo  0 KiB
[ebuild  N     ] mail-mta/opensmtpd-7.8.0_p1::gentoo  USE="mta pam (split-usr) -berkdb -verify-sig" 729 KiB
[uninstall     ] mail-mta/nullmailer-2.2-r2::gentoo  USE="ssl -test" 
[blocks b      ] mail-mta/opensmtpd[mta(+)] ("mail-mta/opensmtpd[mta(+)]" is soft blocking mail-mta/nullmailer-2.2-r2)
[blocks b      ] mail-mta/nullmailer ("mail-mta/nullmailer" is soft blocking mail-mta/opensmtpd-7.8.0_p1)

Total: 5 packages (5 new, 1 uninstall), Size of downloads: 729 KiB
Conflict: 2 blocks (all satisfied)