Code snippets are from the Scala REPL.
This is perfectly legal Scala even though it is not very useful:
scala> class Test { private val xs = scala.collection.mutable.ArrayBuffer[Int]() private val func = Some((x: Int)=>{ }) private var opt: Option[(Int)=>Unit] = None opt = func } defined class Test However, if I try to do something inside func the code will not compile:
scala> class Test { private val xs = scala.collection.mutable.ArrayBuffer[Int]() private val func = Some((x: Int)=>{ xs += x }) private var opt: Option[(Int)=>Unit] = None opt = func } <console>:13: error: type mismatch; found : Some[Int => Test.this.xs.type] required: Option[Int => Unit] opt = func ^ Instead it produces the type mismatch error and lists the types found and required. While this error message is useful, I don't know how to fix it. My next attempt was this:
scala> class Test { private val xs = scala.collection.mutable.ArrayBuffer[Int]() private val func = Some((x: Int)=>{ xs += x Unit }) private var opt: Option[(Int)=>Unit] = None opt = func } <console>:14: error: type mismatch; found : Some[Int => Unit.type] required: Option[Int => Unit] opt = func ^ I understand that there is a type mismatch occurring, but I don't understand why there is a type mismatch or how to fix it in such a way that I can do something useful inside func.
Why is there a type mismatch and how can it be fixed?
