diff --git a/nixos/modules/services/development/hoogle.nix b/nixos/modules/services/development/hoogle.nix
index 6d6c88b9b2a..bd55483f46d 100644
--- a/nixos/modules/services/development/hoogle.nix
+++ b/nixos/modules/services/development/hoogle.nix
@@ -41,6 +41,7 @@ in {
     haskellPackages = mkOption {
       description = "Which haskell package set to use.";
       default = pkgs.haskellPackages;
+      type = types.package;
       defaultText = "pkgs.haskellPackages";
     };