@NotNull
  default GroovyResolveResult advancedResolve() {
    Collection<? extends GroovyResolveResult> results = resolve(false);
    if (results.size() == 1) {
      return getFirstItem(results);
    }
    else {
      return EmptyGroovyResolveResult.INSTANCE;
    }
  }
@NotNull
  default GroovyResolveResult advancedResolve()