t6335.scala:6: error: method Z is defined twice
  conflicting symbols both originated in file 't6335.scala'
  implicit class Z[A](val i: A) { def zz = i }
                 ^
t6335.scala:3: error: method X is defined twice
  conflicting symbols both originated in file 't6335.scala'
  implicit class X(val x: Int) { def xx = x }
                 ^
two errors found