scalac LOL

innocuous.scala

object Foo {                                                                                                                                                                                                                                                                           
  def foo(x: Int, y: Int = 10) = x*y                                                                                                                                                                                                                                                   
  lazy val y = foo(x = 20)                                                                                                                                                                                                                                                             
}

// innocuous.scala:3: error: variable definition needs type because 'y' is used as a named argument in its body.
// Error occurred in an application involving default arguments.
//   lazy val y = foo(x = 20)
//            ^
// one error found