diff --git a/lib/modules.nix b/lib/modules.nix
index f953b9e62a68..a84ffd2d9aa6 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -1193,11 +1193,8 @@ let
       # original singleton straight to the type merge.
       if
         length defs == 1
-        && (
-          let
-            d = head defs;
-          in
-          addErrorContext "while evaluating definitions from `${d.file}':" (!d.value ? _type)
+        && addErrorContext "while evaluating definitions from `${(head defs).file}':" (
+          !(head defs).value ? _type
         )
       then
         {