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

Calculating dependencies ... done!
Dependency resolution took 1.50 s (backtrack: 0/20).

[ebuild     UD ] sys-devel/bison-3.8.2-r2::gentoo [3.8.2-r3::gentoo] USE="nls -examples -static -test -verify-sig" 2752 KiB

Total: 1 package (1 downgrade), Size of downloads: 2752 KiB