SO bug in inferExprAlternative

gistfile1.scala

trait Base[T]

trait Foo[T] extends Base[T] {

}

object Impl {

  implicit def f[Z](a: Foo[Z]): Result = null
  implicit def f[Z](a: Base[Z]): Result = null
}

//import Impl._

trait Result

object Foo {
  def apply[T](a: Int): Base[T] = new Foo[T]{}
  def apply[T](z: String="abc"): Base[T] = new Foo[T]{}
//  def apply[T]: Foo[T] = new Foo[T]{}
}

object Test {
//  def test[T]: Base[T] = Foo[T]
  def test[T]: Int = Foo[T]
//  def test[T]: Result = Foo[T]
}