typeAliases3.kt

typealias ItemAction = (Item, Int, Boolean) -> Unit

open class ViewHolder(view: View, val action: ItemAction? = null) : RecyclerView.ViewHolder(view) {
    // ...
}

class AViewHolder(view: View, action: ItemAction? = null) : ViewHolder(view, action) {
    // ...
}

class BViewHolder(view: View, action: ItemAction? = null) : ViewHolder(view, action) {
    // ...
}