`variant` does not name a *tuple* variant or *tuple* struct for data-less variant

``` rust
enum A {
    V {}
}

fn main(){ 
    match (A::V {}) {
        A::V => {}
    }
}
```

results in

```
error: `A::V` does not name a tuple variant or a tuple struct [--explain E0164]
 --> <anon>:7:9
7 |>         A::V => {}
  |>         ^^^^
```

instead of pointing user out that this variant is struct-like and they forgot to match on it properly.
