I know this question has been asked before, but either the answers don't apply to this case, or I don't understand them. Basically, why doesn't the following (simple example that recreates my problem) work ?
Making Test covariant in T means that Test[A] is a subtype of Test[Any] for any A. So lets create a Test:
* Scala Gossic : 繼續深入 - 型態參數化 (Covariance)