Macro fed::fed

macro_rules! fed {
    ($($a:ty),+,) => { ... };
    ($a:ty) => { ... };
    ($a:ty, $b:ty) => { ... };
    ($a:ty, $b:ty, $c:ty) => { ... };
    ($a:ty, $b:ty, $c:ty, $d:ty) => { ... };
    ($a:ty, $b:ty, $c:ty, $d:ty, $e:ty) => { ... };
    ($a:ty, $b:ty, $c:ty, $d:ty, $e:ty, $f:ty) => { ... };
    ($a:ty, $b:ty, $c:ty, $d:ty, $e:ty, $f:ty, $g:ty) => { ... };
    ($a:ty, $b:ty, $c:ty, $d:ty, $e:ty, $f:ty, $g:ty, $h:ty) => { ... };
}

Macro to implement type federation traits for federations of concrete types