TupleBinder fails to bind

[tkrs]

TupleBinder is automatically generated as follows:

trait TupleBinder {

  implicit def tuple1Binder[A](implicit
    a: RowSerializer[A]
  ): Binder[Tuple1[A]] =
    new Binder[Tuple1[A]] {
      def apply(bound: BoundStatement, ver: ProtocolVersion, xs: Tuple1[A]): Result[BoundStatement] =
        (a(bound, 0, xs._1, ver)).map(_ => bound)
    }

  implicit def tuple2Binder[A, B](implicit
    a: RowSerializer[A], b: RowSerializer[B]
  ): Binder[(A, B)] =
    new Binder[(A, B)] {
      def apply(bound: BoundStatement, ver: ProtocolVersion, xs: (A, B)): Result[BoundStatement] =
        (a(bound, 0, xs._1, ver) *> b(bound, 1, xs._2, ver)).map(_ => bound)
    }

  implicit def tuple3Binder[A, B, C](implicit
    a: RowSerializer[A], b: RowSerializer[B], c: RowSerializer[C]
  ): Binder[(A, B, C)] =
    new Binder[(A, B, C)] {
      def apply(bound: BoundStatement, ver: ProtocolVersion, xs: (A, B, C)): Result[BoundStatement] =
        (a(bound, 0, xs._1, ver) *> b(bound, 1, xs._2, ver) *> c(bound, 2, xs._3, ver)).map(_ => bound)
    }

  // ...
}

Even though BoundStatement has been immutable since 4.0, all bind operations are discarded because the passed bound is always returned.