anchor.diff:          if (tp == proto[i]) choices.add('$paramName$i');
         }
       }
  -    // Remove possible modification of the iteration variable from the loop
  -    // body.
  +    // Make modification of the iteration variable from the loop
  +    // body less likely.
       if (isLhs) {
  -      if (rand.nextInt(10) != 0) {
  +      if (rand.nextInt(100) != 0) {
           Set<String> cleanChoices = choices.difference(Set.from(iterVars));
           if (cleanChoices.isNotEmpty) {
             choices = cleanChoices;
  
positive.code: // Version of DartFuzz. Increase this each time changes are made
  // to preserve the property that a given version of DartFuzz yields
  // the same fuzzed program for a deterministic random seed.
  const String version = '1.30';
  
  // Restriction on statements and expressions.
  const int stmtLength = 2;
  
negative.code:   void emitMain() {
      emitLn('main() {');
      indent += 2;
  
      // Call each global method once.
      for (int i = 0; i < globalMethods.length; i++) {
        emitLn('try {');
        indent += 2;
        emitLn("", newline: false);
        emitCall(1, "$methodName${i}", globalMethods[i]);
        emit(";", newline: true);
        indent -= 2;
        emitLn('} catch (exception, stackTrace) {');
        indent += 2;
        emitLn("print('$methodName$i throws');");
        indent -= 2;
        emitLn('}');
      }
  
      // Call each class method once.
      for (int i = 0; i < classMethods.length; i++) {
        emitLn("X${i} x${i} = new X${i}();");
        for (int j = 0; j < classMethods[i].length; j++) {
          emitLn('try {');
          indent += 2;
          emitLn("", newline: false);
          emitCall(1, "x${i}.$methodName${i}_${j}", classMethods[i][j]);
          emit(";", newline: true);
          indent -= 2;
          emitLn('} catch (exception, stackTrace) {');
          indent += 2;
          emitLn("print('x${i}.$methodName${i}_${j} throws');");
          indent -= 2;
          emitLn('}');
        }
      }
  
      emitLn('try {');
      indent += 2;
      emitLn('new X${classFields.length - 1}().run();');
      indent -= 2;
      emitLn('} catch (exception, stackTrace) {');
      indent += 2;
      emitLn("print('new X${classFields.length - 1}().run() throws');");
      indent -= 2;
      emitLn('} finally {');
      indent += 2;
  