anchor.diff:  }
   
   class IDLAnnotations extends IDLDictNode {
  -  IDLAnnotations(List annotations) {
  +  IDLAnnotations(List annotations) : super() {
       for (var annotation in annotations) {
         map[annotation.id] = annotation;
       }
  
positive.code: 
  class IDLAnnotation extends IDLDictNode {
    String id;
    IDLAnnotation(String this.id, List args) {
      setMap(args);
    }
  
  
negative.code: }
  
  class IDLExtAttrs extends IDLDictNode {
    IDLExtAttrs([List attrs = const []]) : super() {
      setMap(attrs);
    }
  
  