anchor.diff:    return coverage;
   }
   
  -void _incrementCountForKey(Map<int, int> counter, int key) {
  -  counter[key] = counter.containsKey(key) ? counter[key]! + 1 : 1;
  +extension _MapExtension<T> on Map<T, int> {
  +  void increment(T key) => this[key] = (this[key] ?? 0) + 1;
   }
   
   Future<String> _getFuncName(
  
positive.code:     if (branchCoverage != null) {
        hits.branchHits ??= <int, int>{};
        forEachLine(branchCoverage.hits!, (line) {
          _incrementCountForKey(hits.branchHits!, line);
        });
        forEachLine(branchCoverage.misses!, (line) {
          hits.branchHits!.putIfAbsent(line, () => 0);
  
negative.code:     }
  
      forEachLine(coverage.hits!, (line) {
        hits.lineHits.increment(line);
        if (hits.funcNames != null && hits.funcNames!.containsKey(line)) {
          hits.funcHits!.increment(line);
        }
      });
      forEachLine(coverage.misses!, (line) {
  