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// see neg/t0764 why this should probably be a pos/ test -- alas something's wrong with existential subtyping (?)
// In all cases when calling "prepend" the receiver 'v'
// has static type NodeAlias[A] or (equivalently) Node { type T = A }.
// Since prepend explicitly returns the singleton type of the receiver,
// the return type of prepend in all cases is "v.type", and so the call
// to "new Main" can be parameterized with any of the following, in order
// of decreasing specificity with a tie for second place:
//
// new Main[v.type](v.prepend)
// new Main[NodeAlias[A]](v.prepend)
// new Main[Node { type T = A }](v.prepend)
// new Main(v.prepend)
// the `fail` comments below denote what didn't compile before SI-8177 fixed all of them
package p1 {
object t0764 {
type NodeAlias[A] = Node { type T = A }
trait Node { outer =>
type T <: Node
def prepend: Node { type T = outer.type } = ???
}
class Main1[A <: Node](v: NodeAlias[A]) {
private[this] def f1 = new Main1(v.prepend) // fail
private[this] def f2 = new Main1[NodeAlias[A]](v.prepend) // fail
private[this] def f3 = new Main1[Node { type T = A }](v.prepend) // fail
private[this] def f4 = new Main1[v.type](v.prepend) // ok
}
class Main2[A <: Node](v: Node { type T = A }) {
private[this] def f1 = new Main2(v.prepend) // fail
private[this] def f2 = new Main2[NodeAlias[A]](v.prepend) // fail
private[this] def f3 = new Main2[Node { type T = A }](v.prepend) // fail
private[this] def f4 = new Main2[v.type](v.prepend) // ok
}
}
}
package p2 {
object t0764 {
type NodeAlias[A] = Node { type T = A }
trait Node { outer =>
type T <: Node
def prepend: NodeAlias[outer.type] = ???
}
class Main1[A <: Node](v: NodeAlias[A]) {
private[this] def f1 = new Main1(v.prepend) // ok! <<========== WOT
private[this] def f2 = new Main1[NodeAlias[A]](v.prepend) // fail
private[this] def f3 = new Main1[Node { type T = A }](v.prepend) // fail
private[this] def f4 = new Main1[v.type](v.prepend) // ok
}
class Main2[A <: Node](v: Node { type T = A }) {
private[this] def f1 = new Main2(v.prepend) // fail
private[this] def f2 = new Main2[NodeAlias[A]](v.prepend) // fail
private[this] def f3 = new Main2[Node { type T = A }](v.prepend) // fail
private[this] def f4 = new Main2[v.type](v.prepend) // ok
}
}
}
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