Is a Path Dependent Type a subtype?

Question

trait A {
  trait B {
    def foo: A.this.B = new B{}
    def bar: A#B      = foo 
    def baz: A.this.B = bar // type mismatch; found : A#B required: A.this.B 
  }
         


        

Answer 1

Yes, it's a path dependent type. Yes, all instances of B are members of A#B. Note that you can't directly construct an instance of A#B, all instances of B must have a reference to the outer A instance