scala: how to define a value class

Question

Quick question regrading how to define a value class in scala

Here is typical example:

class Wrapper(val underlying: Int) extends AnyVal

Answer 1

It seems you're doing

class Foo {
  class Wrapper(val underlying: Int) extends AnyVal
}

which you can't. You have to do

class Foo {
}
class Wrapper(val underlying: Int) extends AnyVal