src/HOL/Tools/Predicate_Compile/code_prolog.ML

     val moded_pred_table' = declare_moded_predicate moded_preds moded_pred_table
     fun mk_literal pol derivation constant_table' t =
       let
         val (p, args) = strip_comb t
         val mode = Predicate_Compile_Core.head_mode_of derivation
-        val name = fst (dest_Const p)
+        val name = dest_Const_name p
 
         val p' = the (AList.lookup (op =) moded_pred_table' (name, (pol, mode)))
         val args' = map (translate_term ctxt constant_table') args
       in
         Rel (p', args')