Why are variables not allowed in alternative patterns?

Often you have "symmetric" matches and want to write things like:

def g(p:(Int,Int)) = p match {
  case (10,n) | (n,10) => println(n)
  case _ => println("nope")
}

This is not allowed, but if every alternative has the same variables with the same types, this shouldn't be a problem, as it could be translated to separate cases:

def g(p:(Int,Int)) = p match {
  case (10,n) => println(n)
  case (n,10) => println(n)
  case _ => println("nope")
}

So why do we have this restriction?