return emitError(loc)
             << dim_pair.index() << "-th dimension should be in the range of [-"
             << rank << ", " << rank << ")";
  }

  return success();
}

LogicalResult VerifyTypeRangesAreCompatible(Operation *op,
                                            TypeRangeWithDesc range0,
                                            TypeRangeWithDesc range1) {
  if (range0.first.size() != range1.first.size()) {

                                          Location loc);

// A type range with description (in singular form) attached to it.
using TypeRangeWithDesc = std::pair<TypeRange, StringRef>;

LogicalResult VerifyTypeRangesAreCompatible(Operation *op,
                                            TypeRangeWithDesc range0,
                                            TypeRangeWithDesc range1);

    TypeRangeWithDesc branch_input{branch_type.getInputs(), desc};
    if (failed(VerifyTypeRangesAreCompatible(op, branch_input, input)))
      return failure();

    desc = branch_name(branch.index()) + " result";
    TypeRangeWithDesc branch_result{branch_type.getResults(), desc};
    if (failed(VerifyTypeRangesAreCompatible(op, branch_result, result)))
      return failure();

    branch_types.push_back(branch_type);

  if (!shape_invariant &&
      failed(VerifyTypeRangesAreCompatible(op, input_type, result_type)))
    return failure();

  // Skip the first pair as the While op operands and body function results does
  // not need to be compatible with each other.
  for (int i = 1; i < kNumRegionTypeLists; ++i)
    if (failed(VerifyTypeRangesAreCompatible(op, input_type, region_types[i])))
      return failure();