Extension methods don't get eta-expanded

[prolativ]

Minimized code

extension (s: String) def x(i: Int): Int = i

val x = "".x

Output

value x is not a member of String.
An extension method was tried, but could not be fully constructed:
    {
      def $anonfun(i: Int): Int = x("")(i)
      closure($anonfun)
    }

Expectation

"".x should evaluate into a lambda just like it works for old style extensions using implicit classes:

implicit class StrOps(s: String) {
  def x(i: Int): Int = i
}

val x = "".x

results with

val x: Int => Int = Lambda$1578/0x00000008011a0040@71897380