anchor.diff:        }
       }
   
  -    for (var p in f.positionalParameters.take(f.requiredParameterCount)) {
  +    for (var p in f.positionalParameters) {
         var jsParam = _emitIdentifier(p.name);
  -      initParameter(p, jsParam);
  -    }
  -    for (var p in f.positionalParameters.skip(f.requiredParameterCount)) {
  -      var jsParam = _emitIdentifier(p.name);
  -      var defaultValue = _defaultParamValue(p);
  -      if (defaultValue != null) {
  -        body.add(js.statement(
  -            'if (# === void 0) # = #;', [jsParam, jsParam, defaultValue]));
  -      }
         initParameter(p, jsParam);
       }
       for (var p in f.namedParameters) {
  
positive.code:       for (var ctor in superclass.constructors) {
          var savedUri = _currentUri;
          _currentUri = ctor.enclosingClass.fileUri;
          var jsParams = _emitParameters(ctor.function);
          _currentUri = savedUri;
          var name = ctor.name.name;
          var ctorBody = [
  
negative.code:       //
        // In the future, we might be able to simplify this, see:
        // https://github.com/dart-lang/sdk/issues/28320
        var jsParams = _emitParameters(function, isForwarding: true);
        var mutatedParams = jsParams;
        var gen = emitGeneratorFn((fnBody) {
          var mutatedVars = js_ast.findMutatedVariables(fnBody);
  