Type inferencing of missing properties that look like method references

Consider the following:
```groovy
class Pogo {
  def bar() {}
  void meth() {
    def baz = bar
    bar = baz
    baz = this.bar
    this.bar = baz
  }
}
```

None of the "bar" tokens within meth() refer to "def bar()" method.  They are property references. All should infer as unknown in this case.  At runtime they all produce a MissingPropertyException.