Overload resolution with FunctionN as expected type

[allanrenucci]

object Test {
  def foo(c: String => Int) = c("Hello")

  def f(x: String): Int = 1
  def f: String => Int = _ => 2

  def main(args: Array[String]): Unit = {
    foo(f) // Dotty: 1, Scala 2: 2
  }
}

Overload resolution differs between Dotty and Scala2. dotc eta-expand the first overload, scalac picks the second overload

[som-snytt]

This is less mystifying now, so it shan't be considered for dotty puzzlers, I'm afraid, despite its glowing recommendation.

➜  snips scala-cli run --server=false -S 2.13.15 i4831.scala
2
➜  snips scala-cli run --server=false -S 3.5.2 i4831.scala
2

Progressed in #19654 for 3.4.1 and backported to 3.3.4.