Package ocaml-variants

Failed to find a solution:

no platform:
2024-07-12 15:45.08 [INFO] Solving for ocaml-base-compiler, ocaml,
                           ocaml-variants using opam_repository_commit 80f59f9d12c0e9dda29eb80811ac7689a7ec392b

2024-07-12 15:46.39 [INFO] base: eliminated all possibilities in 1.27 s

2024-07-12 15:46.39 [INFO] = base =

2024-07-12 15:46.39 [INFO] Can't find all required versions.
Selected: base-bigarray.base base-domains.base base-nnp.base
          base-threads.base base-unix.base conf-pkg-config.3 conf-unwind.0
          ocaml-config.3 ocaml-variants&ocaml&ocaml-base-compiler
          ocaml-base-compiler ocaml-base-compiler ocaml base-domains
- ocaml -> ocaml.5.1.0
    User requested <= 5.1.1
    ocaml-variants 5.1.0+tsan requires = 5.1.0
- ocaml-base-compiler -> (problem)
    User requested >= 4.04.1
    Rejected candidates:
      ocaml-base-compiler.5.2.0: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.2.0~rc1: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.2.0~beta2: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.2.0~beta1: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ocaml-base-compiler.5.2.0~alpha1: In same conflict class (ocaml-core-compiler) as ocaml-variants
      ...
- ocaml-variants -> ocaml-variants.5.1.0+tsan
    User requested = 5.1.0+tsan