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

Calculating dependencies... done!

emerge: there are no ebuilds to satisfy ">=app-eselect/eselect-ruby-20151229".
(dependency required by "dev-lang/ruby-2.3.0::gentoo" [ebuild])
(dependency required by "dev-ruby/json-1.8.3::gentoo[ruby_targets_ruby23]" [ebuild])
(dependency required by "dev-ruby/rdoc-4.2.2::gentoo[ruby_targets_ruby21]" [ebuild])
(dependency required by "dev-lang/ruby-2.0.0_p648::gentoo[rdoc]" [ebuild])
(dependency required by "dev-ruby/rake-11.1.1::gentoo[ruby_targets_ruby20]" [ebuild])
(dependency required by "dev-ruby/racc-1.4.14::gentoo[-test,ruby_targets_ruby20]" [ebuild])