I noticed there is a method called `deferredMembers` in `Type`. Did you try using that, instead of `members` and the filter here? I think the `isIncompleteIn` might be wrong (see the scaladoc below).

```
    /** A a member of class `base` is incomplete if
     *  (1) it is declared deferred or
     *  (2) it is abstract override and its super symbol in `base` is
     *      nonexistent or incomplete.
     *
     *  @param base ...
     *  @return     ...
     */
    final def isIncompleteIn(base: Symbol): Boolean =
```