macro_rules! many_args {
([$($t:tt)*]#$($h:tt)*) => {
many_args!{[$($t)*$($t)*]$($h)*}
};
([$($t:tt)*]) => {
fn _f($($t: ()),*) {} //~ ERROR function can not have more than 65535 arguments
}
many_args!{[_]########## ######}
fn main() {}