def apply(i: Int): Test.Two = new Test.Two(i)

warning: method g in object Test does nothing other than call itself recursively
  def g: Int = g
               ^
1 warning

7 |  def f(i: Int): Int = f(i)
  |  ^^^^^^^^^^^^^^^^^^^^^^^^^
  |  Infinite recursive call
8 |  def g: Int = g
  |  ^^^^^^^^^^^^^^
  |  Infinite recursive call
2 warnings found

    final module class Two() extends Object {
      def apply(i: Int): Test.Two =
        {
          var $this$tailLocal1: (Test.Two : Test.Two) = this
          while <empty> do
            tailLabel1[Unit]:
              return
                {
                  $this$tailLocal1 = Test.Two
                  (return[tailLabel1] ()):Test.Two
                }
        }
    }
    def f(i: Int): Int =
      {
        while <empty> do tailLabel2[Unit]: return (return[tailLabel2] ()):Int
      }

//> using scala 3.7.0

object Test {
  object Two {
    def apply(i: Int): Test.Two.type = Test.Two(i)
  }
}

object app extends App {
  Test.Two(1)
}

//> using scala 3.7.0

object Test {
  object Two {
    def apply(i: Int): Two.type = Two(i)
  }
}

object app extends App {
  Test.Two(1)
}

[warn] Infinite recursive call
[warn]     def apply(i: Int): Two.type = Two(i)
[warn]     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^