a.scala

class A(val value: Int) {
  def +(b: Int): A = new A(value + b)
}

object A {
  def >(a: Int): A = new A(a)
}

// ok
(A > 1 + 2 + 3).value

b.scala

trait T

trait T1 extends T
trait T2 extends T
trait T3 extends T

trait Val[D]{
  def value:Int
}

object Val{
  def con[D](v:Int)=new Val[D] {
    override def value = v
  }
}

val v1 = Val.con[T1](1)
val v2 = Val.con[T2](2)
val v3 = Val.con[T3](3)

class B[S](val value: Int) {
  def +[D](b: Val[D]): B[(S, D)] = new B[(S, D)](value + b.value)
}

object B {
  def >[D](a: Val[D]): B[D] = new B[D](a.value)
}

// ok
(B > v1).value

// ok
((B > v1) + v2).value

// Error
(B > v1 + v2).value

SparseTensorFactory.scala

class SparseTensorFactory[Shape](sv: ShapeValue[Shape]) {
  def *[D <: Dimension](dv: DimValue[D]): SparseTensorFactory[Shape ~ D] =
    new SparseTensorFactory[Shape ~ D](sv.append(dv))

  def &(sc: SparkContext): SparseTensor[Shape] =
    new SparseTensor[Shape](sc, sv)
}

object SparseTensorFactory {
  def >[D <: Dimension](dv: DimValue[D]): SparseTensorFactory[RNil ~ D] =
    new SparseTensorFactory[RNil ~ D](dv)
}

trait Dim1 extends VarDim

trait Dim2 extends VarDim

val dim1 = DimValue[Dim1](2)
val dim2 = DimValue[Dim2](3)

// Error:(36, 40) value * is not a member of org.chaomai.tensor.DimValue[Dim1]
val t = SparseTensorFactory > dim1 * dim2