Why it does not allow to assign descendant class ?...

# announcements

[o.semen]

Why it does not allow to assign descendant class ?

interface TopicDelegate<T: ProfileItem> {
    val title: Int
}

class DistrictDelegate(val api: INetworkApi): TopicDelegate<District> {
    override val title: Int = R.string.choose_districts
}

abstract class TopicFragment<T: ProfileItem> : BaseFragment() {
    private var modeDelegate: TopicDelegate<T> = DistrictDelegate(mNetworkApi) //does not work
    //Type mismatch. Required: TopicDelegate<T> Found: DistrictDelegate
}

[diesieben07]

DistrictDelegate is a TopicDelegate<District>, but a TopicDelegate<T> is required. T might not be District.

[o.semen]

District extends ProfileItem
so TopicDelegate<District> should fit into TopicDelegate<T: ProfileItem> right ?

[diesieben07]

No. T is a parameter, it may stand for anything that extends ProfileItem. So if T is actually a SomeOtherProfileItem, you can't put a District in there.