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/common-sense-3.750.0::gentoo  PERL_FEATURES="ithreads (-debug) -quadmath" 14 KiB
[ebuild  N     ] dev-perl/Canary-Stability-2013.0.0::gentoo  PERL_FEATURES="ithreads (-debug) -quadmath" 5 KiB
[ebuild  N     ] dev-perl/Types-Serialiser-1.10.0::gentoo  USE="-test" PERL_FEATURES="ithreads (-debug) -quadmath" 7 KiB
[ebuild  N     ] dev-perl/JSON-XS-4.40.0::gentoo  USE="-examples -test" PERL_FEATURES="ithreads (-debug) -quadmath" 86 KiB

Total: 4 packages (4 new), Size of downloads: 110 KiB