Fix type inferencing and syntax highlighting for this.name within map-based type

[eric-milles]

Consider the following:

abstract class A extends HashMap<String,Object> {
  def one, two = { -> }
}

class C extends A {
  def three
  void test() {
    one
    two()
    three
    empty
    isEmpty();
    { ->
      one
      two()
      three
      empty
      isEmpty()
    }
  }
}

[eric-milles]

This is consistent with runtime behavior.