When error is encountered in the types, the real type is lost. Need to have a way to get the original type despite of the error type.
This is reported/needed by NetBeans.

An example is the following code...

import java.util.*;
class FooBar {
  void fooBar() {
    Iterator<Number> itr = null;
    String str = itr.next();
  }
}

In the code above the type of itr.next() is ErrorType. (The initialization is invalid.) Tools need to have a way to get the "original" type, so they can perform code manipulations.