anchor.diff:      return body.block.statements.single;
     }
   
  -  CompilationUnit _parseUnit(String code) {
  +  CompilationUnit _parseUnit(String code, {FeatureSet? featureSet}) {
       GatheringErrorListener listener = GatheringErrorListener();
       CharSequenceReader reader = CharSequenceReader(code);
  -    var featureSet = FeatureSet.forTesting(sdkVersion: '2.2.2');
  +    featureSet ??= FeatureSet.forTesting(sdkVersion: '2.2.2');
       Scanner scanner = Scanner(TestSource(), reader, listener)
         ..configureFeatures(
           featureSetForOverriding: featureSet,
  
positive.code: 
    void test_visitAnnotation_constructor() {
      _assertCloneUnitMember('@A.c() main() {}');
    }
  
    void test_visitAnnotation_withComment() {
  
negative.code:     _assertClone(node);
    }
  
    void _assertCloneUnitMember(String code, {FeatureSet? featureSet}) {
      AstNode node = _parseUnitMember(code, featureSet: featureSet);
      _assertClone(node);
    }
  
  