Question

Consider the following typical Scala ‘pimp’ code:

class PimpedA(a:A){
  def pimp() = "hi"
}
implicit def pimpA(a:A) = new PimpedA(a)

new A(){
  pimp()  //<--- does not compile
}

However, changing it to:

new A(){
  this.pimp()
}

Makes it work.
Shouldn’t it be the same to the Scala compiler?

EDIT : Is there any solution that can make it work without having to add the this.?

Answer 1

In this case you should give compiler a hint that pimp() is not a random function. When you write

this.pimp()

compiler know there isn’t pimp function on class A so it’s an error and before giving up it searches implicit conversion in scope and finds it.

pimpA(this).pimp()

And when you just call pimp() compiler doesn’t know what object to pass to the pimpA(a: A) implicit function.

UPDATE

It is hard to understand what is your goal. I can only suggest to make PimpedA a typeclass (Pimp[T] in this example).

trait Pimp[T] {
  def action(p: T): String
}  

implicit object PimpA extends Pimp[A] {
  override def action(p: A) = "some actions related to A"
}

def pimp[T: Pimp](p: T) = implicitly[Pimp[T]].action(p)

class A {
  val foo = pimp(this)
}

scala> new A foo
res2: String = some actions related to A