diff --git a/pkgs/applications/networking/sync/unison/default.nix b/pkgs/applications/networking/sync/unison/default.nix
index cada3f93f55a..c29bd3a486cc 100644
--- a/pkgs/applications/networking/sync/unison/default.nix
+++ b/pkgs/applications/networking/sync/unison/default.nix
@@ -1,6 +1,8 @@
-{stdenv, fetchFromGitHub, ocaml, lablgtk, fontschumachermisc, xset, makeWrapper, ncurses
+{stdenv, fetchFromGitHub, ocamlPackages, fontschumachermisc, xset, makeWrapper, ncurses
 , enableX11 ? true}:
 
+let inherit (ocamlPackages) ocaml lablgtk; in
+
 stdenv.mkDerivation (rec {
 
   pname = "unison";
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 57830fcea6f4..db737c3e2a6e 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -22045,7 +22045,10 @@ in
 
   unigine-valley = callPackage ../applications/graphics/unigine-valley { };
 
-  inherit (ocaml-ng.ocamlPackages_4_05) unison;
+  unison = callPackage ../applications/networking/sync/unison {
+    enableX11 = config.unison.enableX11 or true;
+    ocamlPackages = ocaml-ng.ocamlPackages_4_05;
+  };
 
   unpaper = callPackage ../tools/graphics/unpaper { };
 
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 002e3bebbb2c..0a3cbc6f1c3a 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -1198,10 +1198,6 @@ let
 
     google-drive-ocamlfuse = callPackage ../applications/networking/google-drive-ocamlfuse { };
 
-    unison = callPackage ../applications/networking/sync/unison {
-      enableX11 = config.unison.enableX11 or true;
-    };
-
     hol_light = callPackage ../applications/science/logic/hol_light { };
 
   })).overrideScope' liftJaneStreet;