diff -r f6c6d0988fba -r 39cd50407f79 src/HOL/Tools/Meson/meson.ML
--- a/src/HOL/Tools/Meson/meson.ML	Tue Aug 13 18:31:40 2024 +0200
+++ b/src/HOL/Tools/Meson/meson.ML	Tue Aug 13 18:53:24 2024 +0200
@@ -541,7 +541,8 @@
 fun nnf_ss simp_options =
   simpset_of (put_simpset HOL_basic_ss \<^context>
     addsimps (nnf_extra_simps simp_options)
-    addsimprocs [\<^simproc>\<open>defined_All\<close>, \<^simproc>\<open>defined_Ex\<close>, \<^simproc>\<open>neq\<close>, \<^simproc>\<open>let_simp\<close>])
+    |> fold Simplifier.add_proc
+      [\<^simproc>\<open>defined_All\<close>, \<^simproc>\<open>defined_Ex\<close>, \<^simproc>\<open>neq\<close>, \<^simproc>\<open>let_simp\<close>])
 
 val presimplified_consts =
   [\<^const_name>\<open>simp_implies\<close>, \<^const_name>\<open>False\<close>, \<^const_name>\<open>True\<close>,