!patternSet.intersect().isEmpty()

        when:
        patternSet = new PatternSet()
        patternSet.exclude { false }
        then:
        !patternSet.isEmpty()
        !patternSet.intersect().isEmpty()

        when:
        patternSet = new PatternSet()
        patternSet.exclude("*.txt")
        then:
        !patternSet.isEmpty()
        !patternSet.intersect().isEmpty()
    }

		}
		fnIdx = gfidx
	}
	if !haveCounters {
		return
	}

	// Install counters in package ctab.
	gfp, ok := mm.p.ctab[fnIdx]
	if ok {
		if verb == "subtract" || verb == "intersect" {
			panic("should never see this for intersect/subtract")
		}
		if *verbflag >= 3 {
			fmt.Printf("counter merge for %s fidx=%d\n", fd.Funcname, fnIdx)
		}
		// Merge.
		err, overflow := mm.MergeCounters(gfp.Counters, counters)

        logger.finer(
            Platform.format(
                "%s: skipping because these features are absent: %s", method, missingFeatures));
      }
      return false;
    }
    if (intersect(features, requirements.getAbsentFeatures())) {
      if (logger.isLoggable(FINER)) {
        Set<Feature<?>> unwantedFeatures = Helpers.copyToSet(requirements.getAbsentFeatures());
        unwantedFeatures.retainAll(features);

        logger.finer(
            Platform.format(
                "%s: skipping because these features are absent: %s", method, missingFeatures));
      }
      return false;
    }
    if (intersect(features, requirements.getAbsentFeatures())) {
      if (logger.isLoggable(FINER)) {
        Set<Feature<?>> unwantedFeatures = Helpers.copyToSet(requirements.getAbsentFeatures());
        unwantedFeatures.retainAll(features);

		t.Fatalf("can't create outdir %s: %v", ioutdir, err)
	}

	// Intersect the two dirs into a final result.
	ins := fmt.Sprintf("-i=%s,%s", indir1, indir2)
	out := fmt.Sprintf("-o=%s", ioutdir)
	sargs := []string{ins, out}
	lines := runToolOp(t, s, "intersect", sargs)
	if len(lines) != 0 {
		t.Errorf("intersect run produced unexpected output: %+v", lines)
	}

		// The type set of an interface is the intersection of the type sets of all its elements.
		// Due to language restrictions, only embedded interfaces can add methods, they are handled
		// separately. Here we only need to intersect the term lists and comparable bits.
		allTerms, allComparable = intersectTermLists(allTerms, allComparable, terms, comparable)
	}

	ityp.tset.comparable = allComparable
	if len(allMethods) != 0 {

		// The type set of an interface is the intersection of the type sets of all its elements.
		// Due to language restrictions, only embedded interfaces can add methods, they are handled
		// separately. Here we only need to intersect the term lists and comparable bits.
		allTerms, allComparable = intersectTermLists(allTerms, allComparable, terms, comparable)
	}

	ityp.tset.comparable = allComparable
	if len(allMethods) != 0 {

   * Returns the intersection of the two ranges, or an empty range if their intersection is empty.
   */
  @SuppressWarnings("nullness") // TODO(cpovirk): Add casts as needed. Will be noisy and annoying...
  GeneralRange<T> intersect(GeneralRange<T> other) {
    checkNotNull(other);
    checkArgument(comparator.equals(other.comparator));

    boolean hasLowBound = this.hasLowerBound;
    T lowEnd = getLowerEndpoint();

   * Returns the intersection of the two ranges, or an empty range if their intersection is empty.
   */
  @SuppressWarnings("nullness") // TODO(cpovirk): Add casts as needed. Will be noisy and annoying...
  GeneralRange<T> intersect(GeneralRange<T> other) {
    checkNotNull(other);
    checkArgument(comparator.equals(other.comparator));

    boolean hasLowBound = this.hasLowerBound;
    T lowEnd = getLowerEndpoint();

        target.excludeSpecs = from.excludeSpecs == null ? null : Sets.newLinkedHashSet(from.excludeSpecs);
    }

    public PatternSet intersect() {
        if (isEmpty()) {
            return new PatternSet(this.patternSpecFactory);
        } else {
            return new IntersectionPatternSet(this);
        }
    }

    /**