anchor.diff:          try {
             log.info('Scanning transitive dependencies...');
             allTransitiveLibs = await libraryScanner.scanTransitiveLibs();
  +          reachableLibs = _reachableLibs(allTransitiveLibs);
           } catch (e, st) {
             log.severe('Error scanning transitive libraries', e, st);
             suggestions.add(new Suggestion.bug(
  
positive.code:           fileAnalyzerItems?.where((cp) => cp.isError)?.toList() ?? const [];
        final platformBlockers =
            codeErrors.where((cp) => cp.isPlatformBlockingError).toList();
        final libPlatformBlocked = platformBlockers.isNotEmpty;
        pkgPlatformBlocked = pkgPlatformBlocked || libPlatformBlocked;
        var uri = toPackageUri(package, dartFile);
        var directLibs = allDirectLibs == null ? null : allDirectLibs[uri];
        var transitiveLibs =
            allTransitiveLibs == null ? null : allTransitiveLibs[uri];
  
negative.code: 
      Map<String, List<String>> allDirectLibs;
      Map<String, List<String>> allTransitiveLibs;
      Set<String> reachableLibs;
  
      LibraryScanner libraryScanner;
  
  