Macro enum_meta::lazy_meta

macro_rules! lazy_meta {
    ($enum_type:ident, $return_type:ty, $storage:ident;
     $($enum_variant:ident, $return_expr:expr);*
    ) => { ... };
    ($enum_type:ident, $return_type:ty, $storage:ident;
     $($enum_variant:ident, $return_expr:expr);+ ;
    ) => { ... };
}