import scala.quoted.*

trait Hammer[I, O] {
  def hammer(input: I): O
}

object Hammer {
  inline def makeProductHammerMacro[I, O](): Hammer[I, O] =
    ${ makeProductHammerMacroImpl[I, O] }

  def makeProductHammerMacroImpl[I: Type, O: Type](using Quotes): Expr[Hammer[I, O]] =
    '{ makeHammer[I, O]() }

  inline def makeHammer[S, O](): Hammer[S, O] =
    new Hammer[S, O] {
      lazy val (hammer: Hammer[?, Int], idx: Int) = ???

      override def hammer(input: S): O = {
        hammer.hammer(???.asInstanceOf).asInstanceOf[O]
      }
    }
}

object HammerSpec {
  case class A(x: Int)
  case class B(x: Int)
  Hammer.makeProductHammerMacro[A, B]()
}

[error] -- [E007] Type Mismatch Error: /Users/jchyb/workspace/community-build3/repo/src/main/scala/com/melvinlow/hammer/instances.scala:5:37 
[error]  5 |  Hammer.makeProductHammerMacro[A, B]()
[error]    |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]    |  Found:    ?1.I
[error]    |  Required: Nothing
[error]    |
[error]    |  where:    ?1 is an unknown value of type Hammer[?, Int]
[error]    |----------------------------------------------------------------------------
[error]    |Inline stack trace
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from Hammer.scala:21
[error] 21 |        hammer.hammer(???.asInstanceOf).asInstanceOf[O]
[error]    |                      ^^^^^^^^^^^^^^^^
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from Hammer.scala:21
[error] 14 |    '{ makeHammer[I, O]() }
[error]    |       ^^^^^^^^^^^^^^^^^^
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from Hammer.scala:21
[error] 14 |    '{ makeHammer[I, O]() }
[error]    |       ^^^^^^^^^^^^^^^^^^
[error]     ----------------------------------------------------------------------------
[error]    |----------------------------------------------------------------------------
[error]    | Explanation (enabled by `-explain`)
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |
[error]    | Tree: ???.asInstanceOf[?1.I]
[error]    | I tried to show that
[error]    |   ?1.I
[error]    | conforms to
[error]    |   Nothing
[error]    | but none of the attempts shown below succeeded:
[error]    |
[error]    |   ==> ?1.I  <:  Nothing
[error]    |     ==> Any  <:  Nothing  = false
[error]    |
[error]    | The tests were made under the empty constraint
[error]     ----------------------------------------------------------------------------