src/HOL/Integ/Integ.ML

 by (safe_tac (!claset));
 by (asm_full_simp_tac (!simpset addsimps [zadd, zminus]) 1);
 by (safe_tac (!claset addSDs [less_eq_Suc_add]));
 by (rename_tac "k" 1);
 by (res_inst_tac [("x","k")] exI 1);
-by (asm_full_simp_tac (!simpset delsimps [add_Suc, add_Suc_right]
-                                addsimps ([add_Suc RS sym] @ add_ac)) 1);
 (*To cancel x2, rename it to be first!*)
-by (rename_tac "a b" 1);
+by (rename_tac "a b c" 1);
+by (Asm_full_simp_tac 1);
 by (asm_full_simp_tac (!simpset delsimps [add_Suc_right]
-                                addsimps (add_left_cancel::add_ac)) 1);
+                                addsimps ([add_Suc_right RS sym] @ add_ac)) 1);
 qed "zless_eq_zadd_Suc";
 
 goalw Integ.thy [zless_def, znegative_def, zdiff_def, znat_def] 
     "z < z + $#(Suc(n))";
 by (res_inst_tac [("z","z")] eq_Abs_Integ 1);