Parameter untupling does not accommodate varargs

[som-snytt]

Compiler version

3.1.0

Minimized code

scala> val xs = List(1->10,2->20)
val xs: List[(Int, Int)] = List((1,10), (2,20))

scala> def f(n: Int*) = n.sum
def f(n: Int*): Int

scala> xs.map(f)
-- Error:
1 |xs.map(f)
  |       ^
  |       Found:    Seq[Int] => Int
  |       Required: ((Int, Int)) => Int

scala> def g(i: Int, j: Int) = i+j
def g(i: Int, j: Int): Int

scala> xs.map(g)
val res0: List[Int] = List(11, 22)

Output

-- Error:

Expectation

Adapt the tuple to my repeated parameter.

Implies #14367

A snag is the spec language that "n > 1". The impedance is def f[A](as: A*) because A can be the arbitrary tuple. But that is fine, it just says the adaptation is not needed.