diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index bb033b23e332..d59b5277e349 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -14038,7 +14038,7 @@ with pkgs;
 
   regina = callPackage ../development/interpreters/regina { };
 
-  inherit (ocamlPackages) reason;
+  inherit (ocaml-ng.ocamlPackages_4_12) reason;
 
   pixie = callPackage ../development/interpreters/pixie { };
   dust = callPackage ../development/interpreters/pixie/dust.nix { };