Macro dispatch_source_enum_inner

macro_rules! dispatch_source_enum_inner {
    (
        {$({$source_variant:ident, $prop_name:ty, $split:ty }),*},
        $enum_name:ident,
        $impl:tt,
        {$inner_name:ident, $prop_type_name:ident, $split_type_name:ident},
        $body:expr
    ) => { ... };
}