diff -r 079fe4292526 -r c7723cc15de8 src/HOL/Metis_Examples/Message.thy
--- a/src/HOL/Metis_Examples/Message.thy	Sun Aug 25 20:54:20 2024 +0200
+++ b/src/HOL/Metis_Examples/Message.thy	Sun Aug 25 21:10:01 2024 +0200
@@ -50,6 +50,8 @@
 text\<open>Concrete syntax: messages appear as \<open>\<lbrace>A,B,NA\<rbrace>\<close>, etc...\<close>
 syntax
   "_MTuple"      :: "['a, args] => 'a * 'b"       ("(2\<lbrace>_,/ _\<rbrace>)")
+syntax_consts
+  "_MTuple"     == MPair
 translations
   "\<lbrace>x, y, z\<rbrace>"   == "\<lbrace>x, \<lbrace>y, z\<rbrace>\<rbrace>"
   "\<lbrace>x, y\<rbrace>"      == "CONST MPair x y"