diff --git a/lib/types.nix b/lib/types.nix
index 0810a43ed0e..77245158d9f 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -457,7 +457,7 @@ rec {
       name = "function that evaluates to a(n) ${elemType.name}";
       check = isFunction;
       merge = loc: defs:
-        fnArgs: elemType.merge loc (map (fn: { inherit (fn) file; value = fn.value fnArgs; }) defs);
+        fnArgs: (mergeDefinitions (loc ++ [ "[function body]" ]) elemType (map (fn: { inherit (fn) file; value = fn.value fnArgs; }) defs)).mergedValue;
       getSubOptions = elemType.getSubOptions;
       getSubModules = elemType.getSubModules;
       substSubModules = m: functionTo (elemType.substSubModules m);