--functions does not account for trait methods dependencies

[mario-bucev]

If we pass --functions=useCalc we get a well-formedness error because compute was not overriden by Iden.

object DashDashFunctions {
  trait Calculator {
    def compute(x: BigInt): BigInt
  }
  case class Iden() extends Calculator {
    override def compute(x: BigInt): BigInt = x + x - x
  }


  def useCalc(c: Calculator): BigInt = {
    val x = c.compute(1)
    x
  }
}

It seems that the dependencies computation does not pull the children implementation.

[mario-bucev]

Maybe there is something to add in the dependency graph override