Type projection on parameterized refinement fails pickling test

[Katrix]

minimized code

type O1[A] = {
  type OutInner[Ts] <: Tuple = Ts match {
    case Unit   => Unit
    case h *: t => h *: OutInner[t]
  }
  
  type Out = OutInner[A]
}

def f1: O1[(Int, Int)]#Out = ???

expectation

The code works fine. If no partial application is used it works fine.
https://scastie.scala-lang.org/IhFycVEdRVmJOjSAtXCw6Q

[OlivierBlanvillain]

Further minimized without match types:

object Main {
  type O1[A] = {
    type OutInner[X] = Unit
    type Out = OutInner[A]
  }

  def f1: O1[Int]#Out = ???
}

error:

-- Error: /home/olivier/7445.scala:9:10 --------------------------------------
9 |  def f1: O1[Int]#Out = ???
  |          ^
  |Recursion limit exceeded.
  |Maybe there is an illegal cyclic reference?
  |If that's not the case, you could also try to increase the stacksize using the -Xss JVM option.
  |A recurring operation is (inner to outer):
  |
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  ...
  |
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member Object#OutInner
  |  find-member O1#OutInner
  |  find-member O1#Out
one error found

[ckipp01]

Trying this out, the minimized version now compiles.

//> using scala 3.3.1-RC1-bin-20230510-d6c643c-NIGHTLY

object Main {
  type O1[A] = {
    type OutInner[X] = Unit
    type Out = OutInner[A]
  }

  def f1: O1[Int]#Out = ???
}

I'm gong to go ahead and close, but feel free to report back if I'm misunderstanding and this issue still persists.

[ckipp01]

I was a bit too eager with closing this. While the minimized version does now compile, the original one has a giant stacktrace that fails the pickling test. I've gone ahead and added tests for these in #17475, but I'll re-open this due to the pickling failure. The stacktrace is literally thousands of lines long, so I didn't include it.