diff -r 5c8177fd1295 -r 8e6c973003c8 src/HOL/Tools/Function/scnp_reconstruct.ML
--- a/src/HOL/Tools/Function/scnp_reconstruct.ML	Wed Oct 20 17:11:46 2021 +0200
+++ b/src/HOL/Tools/Function/scnp_reconstruct.ML	Wed Oct 20 18:13:17 2021 +0200
@@ -63,7 +63,6 @@
 (
   type T = multiset_setup option
   val empty = NONE
-  val extend = I;
   val merge = merge_options
 )