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

Calculating dependencies ... done!
Dependency resolution took 1.67 s (backtrack: 8/20).

[ebuild  N     ] dev-lang/ocaml-4.14.2:0/4.14.2::gentoo  USE="ocamlopt -emacs -flambda -latex -xemacs" 5377 KiB
[ebuild  N     ] dev-ml/dune-3.23.1:0/3.23.1::gentoo  USE="-emacs -test" 3624 KiB
[ebuild  N     ] dev-ml/findlib-1.9.8::gentoo  USE="ocamlopt -doc -tk" 269 KiB
[ebuild  N     ] dev-ml/result-1.5:0/1.5::gentoo  USE="ocamlopt" 3 KiB
[ebuild  N     ] dev-ml/ocamlbuild-0.16.1:0/0.16.1::gentoo  USE="ocamlopt" 198 KiB
[ebuild  N     ] dev-ml/ppx_derivers-1.2.1:0/1.2.1::gentoo  USE="ocamlopt" 3 KiB
[ebuild  N     ] dev-ml/sexplib0-0.17.0-r2:0/0.17::gentoo  USE="ocamlopt" 23 KiB
[ebuild  N     ] dev-ml/ocaml-migrate-parsetree-2.4.0-r1:0/2.4.0::gentoo  USE="ocamlopt -test" 203 KiB
[ebuild  N     ] dev-ml/ocaml-compiler-libs-0.12.4-r2:0/0.12.4::gentoo  USE="ocamlopt" 6 KiB
[ebuild  N     ] dev-ml/yojson-3.0.0:0/3.0.0::gentoo  USE="ocamlopt -examples -test" 56 KiB
[ebuild  N     ] dev-ml/cppo-1.8.0:0/1.8.0::gentoo  USE="ocamlopt" 43 KiB
[ebuild  N     ] dev-ml/topkg-1.1.1:0/1.1.1::gentoo  USE="ocamlopt" 119 KiB
[ebuild  N     ] dev-ml/ppx_tools-6.6-r1:0/6.6::gentoo  USE="ocamlopt" 19 KiB
[ebuild  N     ] dev-ml/cmdliner-2.1.0:0/2.1.0::gentoo  USE="ocamlopt" 96 KiB
[ebuild  N     ] dev-ml/ppxlib-0.39.0:0/0.39.0::gentoo  USE="ocamlopt -test" 687 KiB
[ebuild  N     ] dev-ml/ppx_deriving-5.2.1-r2:0/5.2.1::gentoo  USE="ocamlopt -test" 46 KiB

Total: 16 packages (16 new), Size of downloads: 10764 KiB

WARNING: One or more updates/rebuilds have been skipped due to a dependency conflict:

dev-lang/ocaml:0

  (dev-lang/ocaml-5.5.1:0/5.5.1::gentoo, ebuild scheduled for merge) USE="ocamlopt -emacs -flambda -latex -test -xemacs" conflicts with
    <dev-lang/ocaml-5 required by (dev-ml/ppx_tools-6.6-r1:0/6.6::gentoo, ebuild scheduled for merge) USE="ocamlopt"
    ^               ^
    <dev-lang/ocaml-5 required by (dev-ml/ocaml-migrate-parsetree-2.4.0-r1:0/2.4.0::gentoo, ebuild scheduled for merge) USE="ocamlopt -test"
    ^               ^


!!! The following update(s) have been skipped due to unsatisfied dependencies
!!! triggered by backtracking:

dev-ml/findlib:0
dev-ml/ocaml-compiler-libs:0