Extern multi-argument constructor invoked incorrectly

[fabiomadge]

class {:extern "ABC"} XYZ {
  var y: bool
  constructor {:extern} Init(x: bool) {
    y := x;
  }
  constructor {:extern} Create(x: bool, z: bool) {
    y := x && z;
  }
}

method Main() {
  var xyz := new XYZ.Init(true);
  print xyz.y, "\n";
  xyz := new XYZ.Create(true, false);
  print xyz.y, "\n";
}

The separator is written to an incorrect writer.