Reuse flow class declaration for class definition

Hi
how can I reuse my class declaration in this case without to copy paste all members in the class definition?

```
declare type A {
a: string;
}

class A extends EventEmitter {

foo() {
this.a // error property not found
}
}
```

I thought flow would recognize that `class` A is an instance of `type` A but it doesn't.