src/Pure/ML/ml_env.ML

--- a/src/Pure/ML/ml_env.ML	Wed Oct 20 17:11:46 2021 +0200
+++ b/src/Pure/ML/ml_env.ML	Wed Oct 20 18:13:17 2021 +0200
@@ -117,7 +117,6 @@
 (
   type T = data;
   val empty = empty_data;
-  val extend = I;
   val merge = merge_data;
 );