*/

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

  CollectionSize(int numElements) {
    this.implied = emptySet();
    this.numElements = numElements;
  }

  CollectionSize(Feature<? super Collection>... implied) {
    // Keep the order here, so that PerCollectionSizeTestSuiteBuilder

 public:
  // Returns number of dimensions.
  virtual absl::Status NumDims(int* num_dims) const = 0;
  // Returns number of elements across all dimensions.
  virtual absl::Status NumElements(int64_t* num_elements) const = 0;
  // Returns size of specified dimension
  //
  // -1 indicates an unknown axis length; this is unreachable for most standard