keySetHashCode.scala

➜  sandbox git:(2.13.x) ~/Applications/bin/scala-runners/scala -212x
Welcome to Scala 2.12.11-bin-d1e9ac0 (Java HotSpot(TM) 64-Bit GraalVM EE 19.2.1, Java 1.8.0_231).
Type in expressions for evaluation. Or try :help.

scala> case class K(var x: Int)
defined class K

scala> val k = K(1)
k: K = K(1)

scala> val m = collection.immutable.HashMap(k -> "hi")
m: scala.collection.immutable.HashMap[K,String] = Map(K(1) -> hi)

scala> val s = m.keySet
s: scala.collection.immutable.Set[K] = Set(K(1))

scala> s.hashCode
res0: Int = 240826701

scala> k.x = 10
k.x: Int = 10

scala> s.hashCode
res1: Int = 240826701

scala>