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

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] app-text/wdiff-1.2.3::gentoo  USE="-experimental -test" 1670 KiB
[ebuild  N     ] dev-util/cwdiff-0.4.0::gentoo  USE="-mercurial" 5 KiB

Total: 2 packages (2 new), Size of downloads: 1674 KiB