#[inline] is allowed on structs inside fns

http://is.gd/mRtTeS causes an error, as expected:

``` rust
#[inline] // error: attribute should be applied to function
struct Foo(usize);

fn main() {
}
```

http://is.gd/POCLQo should cause the same error, but is allowed:

``` rust
fn main() {
    #[inline]
    struct Foo(usize);
}
```
