diff --git a/lib/types/custom.nix b/lib/types/custom.nix
index c42cd2ce..ace9ff1c 100644
--- a/lib/types/custom.nix
+++ b/lib/types/custom.nix
@@ -3,13 +3,11 @@
   inherit (lib.strings) isString stringLength match;
   inherit (lib.types) listOf mkOptionType;
 in {
-  mergelessListOf = elemType: let
-    super = listOf elemType;
-  in
-    super
-    // {
+  mergelessListOf = elemType:
+    mkOptionType {
       name = "mergelessListOf";
-      description = "mergeless ${super.description}";
+      description = "mergeless list of ${elemType.description or "values"}";
+      check = listOf elemType.check or (x: true);
       merge = mergeEqualOption;
     };
 
diff --git a/lib/types/dag.nix b/lib/types/dag.nix
index a42ed513..6d289e27 100644
--- a/lib/types/dag.nix
+++ b/lib/types/dag.nix
@@ -62,7 +62,13 @@ in rec {
       inherit (elemType) getSubModules;
       getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
       substSubModules = m: dagOf (elemType.substSubModules m);
-      functor = (defaultFunctor name) // {wrapped = elemType;};
+      functor = {
+        name = name;
+        type = dagOf;
+        wrapped = elemType;
+        payload = elemType;
+        binOp = a: b: a;
+      };
       nestedTypes.elemType = elemType;
     };
 }