void dl_query_ask_for_last_arg(context & ctx, func_decl * pred, relation_fact & f, bool should_be_successful) {
ast_manager & m = ctx.get_manager();
expr_ref_vector query_args(m);
push_into_vector(query_args, f);
query_args.pop_back();
query_args.push_back(m.mk_var(0, pred->get_domain(query_args.size())));
app * query = ctx.get_manager().mk_app(pred, query_args.c_ptr());
lbool is_sat = ctx.query(query);
std::cerr << "@@ last arg query should succeed: " << should_be_successful << "\n";
SASSERT(is_sat != l_undef);
relation_fact res_fact(m);
res_fact.push_back(f.back());
if(ctx.result_contains_fact(res_fact)!=should_be_successful) {
std::cerr<<"wrong arg query answer!\n";
UNREACHABLE();
}
}
