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

Calculating dependencies ... done!
Dependency resolution took 1.04 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/jansson-2.15.1:0/4::gentoo  USE="-doc -static-libs" 478 KiB
[ebuild  N     ] app-eselect/eselect-ctags-1.20::gentoo  9 KiB
[ebuild  N     ] dev-util/ctags-6.2.1::gentoo  USE="json pcre seccomp -test -xml -yaml" 3049 KiB
[ebuild  N     ] app-vim/tagbar-2.7-r1::gentoo  58 KiB

Total: 4 packages (4 new), Size of downloads: 3593 KiB