LuaUserData can't be used with generics

[Shatur]

The following code:

use std::marker::PhantomData;
use luars::LuaUserData;


#[derive(LuaUserData)]
struct Test<T> {
    a: u8,
    marker: PhantomData<T>,
}

Results in

error[E0107]: missing generics for struct `lua::Test`
 --> tests/luars.rs:8:12
  |
8 |     struct Test<T> {
  |            ^^^^ expected 1 generic argument
  |
note: struct defined here, with 1 generic parameter: `T`
 --> tests/luars.rs:8:12
  |
8 |     struct Test<T> {
  |            ^^^^ -
help: add missing generic argument
  |
8 |     struct Test<T><T> {
  |                +++