* is the only one in use, but if we encounter nested concatenations, we start a deque of
     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.

     * is the only one in use, but if we encounter nested concatenations, we start a deque of
     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.

                                       Value item_rank, Type result_type,
                                       PatternRewriter *rewriter) {
  // Create the start position of slice. This is done by concatenating
  // `start_index` and `partial_start_position` together.
  IntegerType shape_dtype = rewriter->getIntegerType(32);
  RankedTensorType position_type =
      tensorflow::GetTypeFromTFTensorShape({-1}, shape_dtype);