diff -r bb6f04c35310 -r 0f4d90a1ae23 src/cx/list.h
--- a/src/cx/list.h	Mon Nov 03 19:55:04 2025 +0100
+++ b/src/cx/list.h	Tue Nov 04 14:31:31 2025 +0100
@@ -1001,7 +1001,7 @@
  * @retval zero when the elements were successfully cloned
  * @retval non-zero when an allocation error occurred
  */
-cx_attr_nonnull_arg(1, 2, 3)
+cx_attr_nonnull_arg(1, 2, 3, 4)
 CX_EXPORT int cxListDifference(CxList *dst,
         const CxList *minuend, const CxList *subtrahend,
         cx_clone_func clone_func, const CxAllocator *clone_allocator, void *data);
@@ -1024,7 +1024,7 @@
  * @retval zero when the elements were successfully cloned
  * @retval non-zero when an allocation error occurred
  */
-cx_attr_nonnull_arg(1, 2, 3)
+cx_attr_nonnull_arg(1, 2, 3, 4)
 CX_EXPORT int cxListIntersection(CxList *dst, const CxList *src, const CxList *other,
         cx_clone_func clone_func, const CxAllocator *clone_allocator, void *data);