code: protected boolean isBrokenPreviousState(IParseResult previousParseResult, int offset) {
  		if (previousParseResult.hasSyntaxErrors()) {
  			BidiTreeIterator<AbstractNode> iterator = ((AbstractNode) previousParseResult.getRootNode()).basicIterator();
  			while(iterator.hasPrevious()) {
  				AbstractNode previous = iterator.previous();
  				if (previous.getGrammarElement() == null) {
  					return true;
  				}
  				if (previous instanceof ILeafNode && previous.getOffset() <= offset) {
  					break;
  				}
  			}
  		}
  		return false;
  	}
docs: Returns true if the previous document state was completely broken, e.g. the parser did not recover at all.
  This may happen e.g. in Xtend for documents like
  <pre>import static class C {}</pre>
  where the class keyword is consumed as an invalid token in the import declaration and everything thereafter
  is unrecoverable.