public Type type_check(Table<Type> t_env,Table<Dec> v_env,boolean in_loop,ErrorList e){
		Type tmp = expr.type_check(t_env, v_env, false, e);
		if(!(tmp.actual() instanceof INT))
			e.add_error("Type of for unary-minus expr should be integer", line, column, "typing");
		the_type = Type.THE_INT;
		return the_type;
	}