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

Calculating dependencies ... done!
Dependency resolution took 2.13 s (backtrack: 6/20).

[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/ocaml-compiler-libs-0.12.4-r2:0/0.12.4::gentoo  USE="ocamlopt" 6 KiB
[ebuild  N     ] dev-ml/ocamlbuild-0.16.1:0/0.16.1::gentoo  USE="ocamlopt" 198 KiB
[ebuild  N     ] dev-ml/sexplib0-0.16.0:0/0.16.0::gentoo  USE="ocamlopt" 22 KiB
[ebuild  N     ] dev-ml/ppx_derivers-1.2.1:0/1.2.1::gentoo  USE="ocamlopt" 3 KiB
[ebuild  N     ] dev-ml/yojson-3.0.0:0/3.0.0::gentoo  USE="ocamlopt -examples -test" 56 KiB
[ebuild  N     ] dev-ml/topkg-1.1.1:0/1.1.1::gentoo  USE="ocamlopt" 119 KiB
[ebuild  N     ] dev-ml/csexp-1.5.2-r1:0/1.5.2::gentoo  USE="ocamlopt -test" 12 KiB
[ebuild  N     ] dev-ml/cmdliner-2.1.0:0/2.1.0::gentoo  USE="ocamlopt" 96 KiB
[ebuild  N     ] dev-ml/dune-configurator-3.21.1:0/3.21.1::gentoo  USE="ocamlopt" 3352 KiB
[ebuild  N     ] dev-ml/ppxlib-0.39.0:0/0.39.0::gentoo  USE="ocamlopt -test" 687 KiB
[ebuild  N     ] dev-ml/base-0.16.3-r1:0/0.16::gentoo  USE="ocamlopt" 433 KiB
[ebuild  N     ] dev-ml/typerep-0.16.0-r1:0/0.16::gentoo  USE="ocamlopt" 23 KiB
[ebuild  N     ] dev-ml/ppx_typerep_conv-0.16.0:0/0.16::gentoo  USE="ocamlopt" 10 KiB

Total: 17 packages (17 new), Size of downloads: 14281 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/typerep-0.16.0-r1:0/0.16::gentoo, ebuild scheduled for merge) USE="ocamlopt"
    ^               ^

dev-ml/sexplib0:0

  (dev-ml/sexplib0-0.17.0-r2:0/0.17::gentoo, ebuild scheduled for merge) USE="ocamlopt" conflicts with
    =dev-ml/sexplib0-0.16*:=[ocamlopt] required by (dev-ml/base-0.16.3-r1:0/0.16::gentoo, ebuild scheduled for merge) USE="ocamlopt"
    ^                ^^^^^            


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

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