Mutual Recursion odd/even

X.scala

scala> :paste
// Entering paste mode (ctrl-D to finish)

import scala.annotation.tailrec

@tailrec
def odd1(n: Int): Boolean = {
  if (n == 0) false
  else even1(n - 1)
}

@tailrec
def even1(n: Int): Boolean = {
  if (n == 0) true
  else odd1(n - 1)
}

// Exiting paste mode, now interpreting.

<console>:14: error: @tailrec annotated method contains no recursive calls
       def odd1(n: Int): Boolean = {
           ^
<console>:20: error: @tailrec annotated method contains no recursive calls
       def even1(n: Int): Boolean = {
           ^