op->getResults());
  }
  if (auto iter_sink = dyn_cast<tf_executor::NextIterationSinkOp>(op)) {
    auto iter_source = cast<tf_executor::NextIterationSourceOp>(
        iter_sink.getToken().getDefiningOp());
    return RefineTypeForPassThroughOperands(
        op, iter_sink.getOperands().drop_front().take_front(),
        iter_source.getResults());
  }

        builder_at_begin.create<mlir::tf_executor::NextIterationSourceOp>(
            loc, operands[0].getType(), result.attributes);
    return builder_.create<mlir::tf_executor::NextIterationSinkOp>(
        loc, source_op.getToken(), operands, result.attributes);
  }
  if (node.IsLoopCond()) {
    return builder_.create<mlir::tf_executor::LoopCondOp>(loc, types, operands,