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

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] sys-fs/mdadm-4.5-r1::gentoo  USE="udev -corosync -static (-systemd)" 700 KiB

Total: 1 package (1 new), Size of downloads: 700 KiB