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

Calculating dependencies ... done!
Dependency resolution took 0.97 s (backtrack: 0/20).

[ebuild  N     ] mail-filter/libmilter-1.0.2_p5:0/1.0.2_p5::gentoo  USE="-poll -verify-sig" 2317 KiB
[ebuild  N     ] acct-group/milter-regex-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/milter-regex-0-r3::gentoo  0 KiB
[ebuild  N     ] mail-filter/milter-regex-2.7-r3::gentoo  21 KiB

Total: 4 packages (4 new), Size of downloads: 2337 KiB