#scala #variances
Similarly, -T would declare T to be used only in contravariant positions.
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Variances - Scala Documentationquot;"
}
object VariancesTest extends App {
var s: Stack[Any] = new Stack().push("hello");
s = s.push(new Object())
s = s.push(7)
println(s)
}
The annotation +T declares type T to be used only in covariant positions. <span>Similarly, -T would declare T to be used only in contravariant positions. For covariant type parameters we get a covariant subtype relationship regarding this type parameter. For our example this means Stack[T] is a subtype of Stack[S] if T is a subtype of S.