[scala] Re: is this a bug?

Adriaan Moors wrote:
> when you write an identifier in a position where a type parameter is
> expected, you introduce a new variable (thus, the "Int" in the above
> snippets does not refer to the existing type Int, but is just some type
> parameter with an unfortunate name)

Yes, I was suffering from a temporary brain-melt when posting that.
Still there's something fishy about my original example, here's a slight
variation:

trait T[A[C] <: T[A, B], B] {
   def x : T[A, B] = y
   def y : A[Int]
}

This indicates to me that the compiler considers that "A[C] <: T[A, B]"
holds for all C. The problem is that now we can define a subtype like this:

class T2[B] extends T[T2, B] { def y = new T2[Int] }

Here's an example how this causes problems:

scala> val t = new T2[Float]
t: T2[Float] = T2@d01311

scala> val t2 = t.x
<console>:7: error: type arguments [T2,Float] do not conform to trait
T's type parameter bounds [A[C] <: T[A,B],B]
        val t2 = t.x
            ^

Clearly something isn't right here.

/Jesper Nordenberg