Macro proc_macro_kwargs::parse_macro_arg_via_syn

macro_rules! parse_macro_arg_via_syn {
    ($target:path) => { ... };
    ($target:path; for <$($lt:lifetime,)* $($param:ident),*> $(where $($where_tks:tt)*)?) => { ... };
}

Implements MacroArg via syn’s Parse trait