private LookupElement @NotNull [] getCurrentExpressionLookupItems() {
    LookupElement[] elements = null;
    try {
      elements = getCurrentExpression().calculateLookupItems(getCurrentExpressionContext());
    }
    catch (IndexNotReadyException ignored) { }
    if (elements == null) return LookupElement.EMPTY_ARRAY;

    return elements;
  }
private LookupElement @NotNull [] getCurrentExpressionLookupItems()