diff -r 8f0b2daa7eaa -r d93ead9ac6df src/HOL/Transitive_Closure.thy
--- a/src/HOL/Transitive_Closure.thy	Thu Jun 12 08:03:05 2025 +0200
+++ b/src/HOL/Transitive_Closure.thy	Thu Jun 12 12:44:47 2025 +0200
@@ -1581,10 +1581,10 @@
 
 setup \<open>
   map_theory_simpset (fn ctxt => ctxt
-    addSolver (mk_solver "Trancl" Trancl_Tac.trancl_tac)
-    addSolver (mk_solver "Rtrancl" Trancl_Tac.rtrancl_tac)
-    addSolver (mk_solver "Tranclp" Tranclp_Tac.trancl_tac)
-    addSolver (mk_solver "Rtranclp" Tranclp_Tac.rtrancl_tac))
+    |> Simplifier.add_unsafe_solver (mk_solver "Trancl" Trancl_Tac.trancl_tac)
+    |> Simplifier.add_unsafe_solver (mk_solver "Rtrancl" Trancl_Tac.rtrancl_tac)
+    |> Simplifier.add_unsafe_solver (mk_solver "Tranclp" Tranclp_Tac.trancl_tac)
+    |> Simplifier.add_unsafe_solver (mk_solver "Rtranclp" Tranclp_Tac.rtrancl_tac))
 \<close>
 
 lemma transp_rtranclp [simp]: "transp R\<^sup>*\<^sup>*"