anchor.diff:  import 'crawl.dart';
   
   main() async {
  -// TODO(pq): make dynamic or update tests to ensure this stays in sync.
   // Uncomment to (re)generate since/linter.yaml contents.
   //  for (var lint in registeredLints) {
   //    var since = await findSinceLinter(lint.name);
  
positive.code:   var sinceMap = <String, SinceInfo>{};
    for (var lint in registeredLints.map((l) => l.name)) {
      var linterVersion = linterVersionCache[lint];
      sinceMap[lint] = new SinceInfo(
          sinceLinter: linterVersion ?? await findSinceLinter(lint),
          sinceDartSdk: await _sinceSdkForLinter(linterVersion));
  
negative.code:         _dartSdkMap[sdk] = linterVersion;
          print('fetched...');
          print('$sdk : $linterVersion');
          print('(consider caching in tool/since/dart_sdk.yaml)');
        }
      }
    }
  