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

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

[ebuild  N     ] dev-perl/YAML-PP-0.39.0-r1::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 212 KiB
[ebuild  N     ] dev-perl/XXX-0.380.0::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 15 KiB

Total: 2 packages (2 new), Size of downloads: 227 KiB