Macro casemappingiter_impls 

macro_rules! casemappingiter_impls {
    (
        #[$stab:meta]
        #[$dendstab:meta]
        #[$fusedstab:meta]
        #[$exactstab:meta]
        #[$displaystab:meta]
        $(#[$attr:meta])*
        $ITER_NAME:ident
    ) => { ... };
}