--- a/src/HOL/Tools/BNF/bnf_def.ML Wed Oct 20 17:11:46 2021 +0200
+++ b/src/HOL/Tools/BNF/bnf_def.ML Wed Oct 20 18:13:17 2021 +0200
@@ -670,7 +670,6 @@
(
type T = bnf Symtab.table;
val empty = Symtab.empty;
- val extend = I;
fun merge data : T = Symtab.merge (K true) data;
);