type selection vs type projection

gistfile1.scala

scala> :pa

class Outer {
  trait Inner  // nested type
  def y = new Inner {}
  def foo(x: Inner) = null         // path-dependent type - same as `def foo(x: this.Inner) = null`
  def bar(x: Outer#Inner) = null   // type projection
}

scala> val x = new Outer
x: Outer = Outer@33dd3a26

scala> val y = new Outer
y: Outer = Outer@7bf7fb55

scala> x.y
res1: x.Inner = Outer$$anon$1@1eb049ba

scala> x.foo(x.y)
res2: Null = null

scala> x.foo(y.y)
<console>:11: error: type mismatch;
 found   : y.Inner
 required: x.Inner
              x.foo(y.y)
                      ^
scala> x.bar(y.y)
res4: Null = null