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

Calculating dependencies ... done!
Dependency resolution took 1.01 s (backtrack: 0/20).

[ebuild  N     ] dev-cpp/tomlplusplus-3.4.0::gentoo  USE="-test" 1265 KiB

Total: 1 package (1 new), Size of downloads: 1265 KiB