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

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

[ebuild  N     ] dev-perl/Struct-Dumb-0.160.0::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 22 KiB
[ebuild  N     ] dev-perl/Future-IO-0.150.0-r1::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 24 KiB

Total: 2 packages (2 new), Size of downloads: 45 KiB