Classes with multiple parameter groups

[jad-hamza]

This is currently not supported by Stainless:

case class C(var x: Int)(var y: Int = x) { }

Variables are only allowed within functions and as constructor parameters in Stainless.

[vkuncak]

Are there uses of such constructors that do not involve partial application? If we need to support partial application, what does C(3) even mean, what is its type?

[mario-bucev]

Mostly for dependent types such as:

case class C(t: MyTrait)(a: MyTrait.A) 

As for C(3), Scala 3 types it as Int => C (as we would expect)

[vkuncak]

I see, so partial application would probably be desugared in Stainless into a partial constructor:

  case class C(var x: Int, var y: Int)

  // replace all C constructor calls with makeC
  def makeC(x: Int)(y: Int) = C(x, y)

  def test: C =
    val pC = makeC(3)
    pC(42)