macro_rules! impl_iter_scan_tuple {
(@impl $($T:ident)*) => { ... };
(@inner $($T:ident)*,) => { ... };
(@inner $($T:ident)*, $U:ident $($Rest:ident)*) => { ... };
($($T:ident)*) => { ... };
}macro_rules! impl_iter_scan_tuple {
(@impl $($T:ident)*) => { ... };
(@inner $($T:ident)*,) => { ... };
(@inner $($T:ident)*, $U:ident $($Rest:ident)*) => { ... };
($($T:ident)*) => { ... };
}