Problem with implicits ...

UnitsEx.scala

object UnitsEx {
  case class Quantity[M <: MInt, T: Numeric](value: T) {
    private val num = implicitly[Numeric[T]]
    def *[M2 <: MInt](m: Quantity[M2, T]) = Quantity[M, T](num.times(value, m.value))
  }

  implicit def measure[T: Numeric](v: T): Quantity[_0, T] = Quantity[_0, T](v)
  implicit def numericToQuantity[T: Numeric](v: T): QuantityConstructor[T] = new QuantityConstructor[T](v)

  class QuantityConstructor[T: Numeric](v: T) {
    def m = Quantity[_1, T](v)
  }

  sealed trait MInt
  final class _0 extends MInt
  final class _1 extends MInt
}

import UnitsEx._

(1 m) * 1 // Works
1 * (1 m) // Doesn't work:
/*
<console>:1: error: overloaded method value * with alternatives:
  (x: Double)Double <and>
  (x: Float)Float <and>
  (x: Long)Long <and>
  (x: Int)Int <and>
  (x: Char)Int <and>
  (x: Short)Int <and>
  (x: Byte)Int
 cannot be applied to (UnitsEx.Quantity[UnitsEx._1,Int])
              1 * (1 m)
                ^
*/