scala> import scala.reflect.runtime.universe._
import scala.reflect.runtime.universe._

scala> class A {
  def foo1(x: Int*) = ???
  def foo2(x: => Int) = ???
  def foo3(x: Any) = ???
  def foo4(x: AnyRef) = ???
  def foo5(x: AnyVal) = ???
  def foo6(x: Null) = ???
  def foo7(x: Nothing) = ???
  def foo8(x: Singleton) = ???
}
defined class A

scala> def test(n: Int): Unit = {
  val sig = typeOf[A] member TermName("foo" + n) info
  val x = sig.asInstanceOf[MethodType].params.head
  println(x.info)
}
warning: there was one feature warning; for details, enable `:setting -feature' or `:replay -feature'
test: (n: Int)Unit

scala> for (i <- 1 to 8) test(i)
scala.Int*
=> scala.Int
scala.Any
scala.AnyRef
scala.AnyVal
scala.Null
scala.Nothing
scala.Singleton

scala> :quit