macro_rules! make_host_trait {
($host_ty:ident, $visitor_ty:ident, $mthd_name:ident, $iter:ident, $($ref:tt)*) => { ... };
}
macro_rules! make_host_trait {
($host_ty:ident, $visitor_ty:ident, $mthd_name:ident, $iter:ident, $($ref:tt)*) => { ... };
}