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/Devel-StackTrace-2.50.0::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 41 KiB
[ebuild  N     ] dev-perl/Class-ReturnValue-0.550.0-r2::gentoo  PERL_FEATURES="ithreads (-debug) -quadmath" 15 KiB

Total: 2 packages (2 new), Size of downloads: 55 KiB