Diamond: compiler accepts erroneous code where diamond is used with non-generic inner class

Compiler accepts the following code:

class A<X> {
   class B { }

   B b = new B<>();
}

Moreover, error messages for the following code is misleading:

class A<X> {
   class B { }

   B b = new A<>.B<>();
}

The above is rejected with:

TestX.java:4: error: improperly formed type, type arguments given on a raw type
   B b = new A<>.B<>();
                  ^

This should simply be a parser error.