failure to infer literal types from literal terms

```scala
  class Foo[T](val value : T) {type Out = T} 
  object Foo {
    def fromXInt[T <: Int with Singleton](i : T): Foo[T] = new Foo[T](i)
  }
  val f1 = Foo.fromXInt(1)
```
```
8 |  val f1 = Foo.fromXInt(1)
  |               ^
  |        Type argument Int does not conform to upper bound Int & Singleton
```