macro_rules! reduce_if_impl {
(co : $co:ty , tr : $tr:ty , fa : $fa:ty , $con:ty => $r:ident < $rt:ident >) => {
impl ExPath for If<$co, $tr, $fa, $con> {
type Lift = <$r<$rt> as ExPath>::Lift;
fn ex_path(&self) -> Self::Lift {
$r {k: self.co.k, i: ()}.ex_path()
}
}
};
}