final class MBufferLong: final def +=(elem: Long): this.type = ??? type M[Tup <: Tuple] <: Tuple = Tup match case EmptyTuple => EmptyTuple case h *: t => BufferOf[h] *: M[t] type M2[T <: Tuple] <: Tuple = (T, M[T]) match case (h *: t, a *: b) => BufferOf[h] *: M2[t] case (EmptyTuple, EmptyTuple) => EmptyTuple case (_, EmptyTuple) => EmptyTuple case (EmptyTuple, _) => EmptyTuple type BufferOf[T] = T match case Long => MBufferLong inline def append[T](t: T, buffer: BufferOf[T]): BufferOf[T] = inline (t, buffer) match case (x: Long, y: BufferOf[Long]) => y.+=(x) buffer transparent inline def appendBuffers[T <: Tuple](t: T, buffers: M[T]): M2[T] = { inline (t, buffers) match case abcd: ((h *: t), bh *: bt) => val (hh *: tt, bh *: bt) = abcd val x: BufferOf[h] = append[h](hh, bh.asInstanceOf[BufferOf[h]]) x *: appendBuffers[t](tt, bt.asInstanceOf[M[t]]) case _: (EmptyTuple, EmptyTuple) => EmptyTuple case _: (_, EmptyTuple) => EmptyTuple case _: (EmptyTuple, _) => EmptyTuple } 

-- [E007] Type Mismatch Error: /Users/wmazur/projects/scala/community-build3/test.scala:26:37 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 26 | val x: BufferOf[h] = append[h](hh, bh.asInstanceOf[BufferOf[h]]) | ^^ | Found: (hh : Any) | Required: h | Note that implicit conversions were not tried because the result of an implicit conversion | must be more specific than h | | where: h is a type in method appendBuffers | | longer explanation available when compiling with `-explain` -- [E007] Type Mismatch Error: /Users/wmazur/projects/scala/community-build3/test.scala:27:28 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 27 | x *: appendBuffers[t](tt, bt.asInstanceOf[M[t]]) | ^^ | Found: (tt : Tuple) | Required: t | | where: t is a type in method appendBuffers with bounds <: Tuple | | longer explanation available when compiling with `-explain`