--- a/src/HOL/Tools/semiring_normalizer.ML Wed Oct 20 17:11:46 2021 +0200
+++ b/src/HOL/Tools/semiring_normalizer.ML Wed Oct 20 18:13:17 2021 +0200
@@ -60,7 +60,6 @@
(
type T = (thm * entry) list;
val empty = [];
- val extend = I;
fun merge data = AList.merge Thm.eq_thm (K true) data;
);