`type X = ::Y` vs `use ::Y as X` mismatch if ::Y is a enum

To reproduce, try to compile this:
```rust
mod foo {
    pub enum Bar { A }
}

// use foo::Bar as Baz; // this works
type Baz = foo::Bar; // this doesn't

fn main() {
    let _ = Baz::A;
}
```
This seems... counterintuitive.