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

Calculating dependencies ... done!
Dependency resolution took 1.51 s (backtrack: 0/20).

[ebuild     UD ] virtual/zlib-1.3.1:0/1::gentoo [1.3.1-r1:0/1::gentoo] USE="-minizip% -static-libs" 0 KiB

Total: 1 package (1 downgrade), Size of downloads: 0 KiB