Chaining Match Types fails at value level

[ThijsBroersen]

reproduction steps

using Scala 3.1.0,

type A[X] = X match
  case Int => Int
  case _   => B[X]

def a[X](x: X): A[X] = x match
  case v: Int => v
  case _      => b(x)

type B[X] = X match
  case String => String

def b[X](x: X): B[X] = x match
  case v: String => v

problem

fails to compile:

Found:    (v : X & Int)
Required: Playground.A[X]
Found:    Playground.B[X]
Required: Playground.A[X]

with some casts it works:

type A[X] = X match
  case Int => Int
  case _   => B[X]

def a[X](x: X): A[X] = (x match
  case v: Int => v
  case _      => b(x)
).asInstanceOf[A[X]]

type B[X] = X match
  case String => String

def b[X](x: X): B[X] = x match
  case v: String => v

[ThijsBroersen]

will move the issue to the dotty repo
scala/scala3#13855