Closed
Description
https://scala3.westeurope.cloudapp.azure.com/job/buildCommunityProject/38542/
Scala version: 3.2.2-RC2
Bisect points to 46e3d77
Reproducer:
def toCsvFlat[A <: Product](a: A)(using m: scala.deriving.Mirror.ProductOf[A]) = {
def flatTuple(any: Any): Tuple = any match
case p: Product => p.productIterator.map(flatTuple).foldLeft(EmptyTuple: Tuple)(_ ++ _)
case a => Tuple1(a)
val tuple = flatTuple(Tuple.fromProductTyped(a)).toList
}Output:
-- [E007] Type Mismatch Error: /workspace/bisect/test.scala:6:51 ---------------
6 | val tuple = flatTuple(Tuple.fromProductTyped(a)).toList
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|Found: List[Tuple.Union[(?1 : Tuple)]]
|Required: List[
| Tuple match {
| case EmptyTuple => Nothing
| case h *: t => h | scala.Tuple.Fold[t, Nothing, [x, y] =>> x | y]
| }
|]
|
|where: ?1 is an unknown value of type Tuple
|
|
|Note: a match type could not be fully reduced:
|
| trying to reduce Tuple.Union[(?1 : Tuple)]
| trying to reduce scala.Tuple.Fold[(?1 : Tuple), Nothing, [x, y] =>> x | y]
| failed since selector (?1 : Tuple)
| does not match case EmptyTuple => Nothing
| and cannot be shown to be disjoint from it either.
| Therefore, reduction cannot advance to the remaining case
|
| case h *: t => h | scala.Tuple.Fold[t, Nothing, [x, y] =>> x | y]
|