anchor.diff:      // Find line with #0 in it.
       String eWithSt = "$e\n\n$st";
       List<String> lines = eWithSt.split("\n");
  -    String foundLine;
  +    String foundLine = "";
  +    int lookFor = 0;
       for (String line in lines) {
  -      if (line.startsWith("#0")) {
  -        foundLine = line;
  -        break;
  +      if (line.startsWith("#$lookFor")) {
  +        foundLine += line;
  +        lookFor++;
  +        if (lookFor >= stackTraceMatches) {
  +          break;
  +        } else {
  +          foundLine += "\n";
  +        }
         }
       }
       if (foundLine == null) throw "Unexpected crash without stacktrace: $e";
       if (expectedCrashLine == null) {
  -      print("Got $foundLine");
  +      print("Got '$foundLine'");
         expectedCrashLine = foundLine;
         return true;
       } else if (foundLine == expectedCrashLine) {
  
positive.code:         byteDelete = true;
        } else if (arg == "--ask-redirect-target") {
          askAboutRedirectCrashTarget = true;
        } else {
          throw "Unknown option $arg";
        }
  
negative.code: String expectedCrashLine;
  bool byteDelete = false;
  bool askAboutRedirectCrashTarget = false;
  int stackTraceMatches = 1;
  Set<String> askedAboutRedirect = {};
  
  main(List<String> arguments) async {
  