anchor.diff:        if (!f(member)) remaining.add(member);
       }
       map[memberName].addAll(remaining);
  -  }
  -
  -  void _processInstanceMembers(String n, bool f(_MemberUsage e)) {
  -    _processSet(_instanceMembersByName, n, f);
  -  }
  -
  -  void _processInstanceFunctions(String n, bool f(_MemberUsage e)) {
  -    _processSet(_instanceFunctionsByName, n, f);
     }
   
     /// Return the canonical [_ClassUsage] for [cls].
  
positive.code:       DynamicUse dynamicUse, MemberUsedCallback memberUsed) {
      Selector selector = dynamicUse.selector;
      String methodName = selector.name;
      switch (dynamicUse.kind) {
        case DynamicUseKind.INVOKE:
          if (_registerNewSelector(dynamicUse, _invokedNames)) {
            _processInstanceMembers(methodName, (_MemberUsage usage) {
              if (dynamicUse.appliesUnnamed(usage.entity, this)) {
                memberUsed(usage.entity, usage.invoke());
                return true;
              }
              return false;
            });
          }
          break;
        case DynamicUseKind.GET:
          if (_registerNewSelector(dynamicUse, _invokedGetters)) {
            _processInstanceMembers(methodName, (_MemberUsage usage) {
              if (dynamicUse.appliesUnnamed(usage.entity, this)) {
                memberUsed(usage.entity, usage.read());
                return true;
              }
              return false;
            });
            _processInstanceFunctions(methodName, (_MemberUsage usage) {
              if (dynamicUse.appliesUnnamed(usage.entity, this)) {
                memberUsed(usage.entity, usage.read());
                return true;
              }
              return false;
            });
          }
          break;
        case DynamicUseKind.SET:
          if (_registerNewSelector(dynamicUse, _invokedSetters)) {
            _processInstanceMembers(methodName, (_MemberUsage usage) {
              if (dynamicUse.appliesUnnamed(usage.entity, this)) {
                memberUsed(usage.entity, usage.write());
                return true;
              }
              return false;
            });
          }
          break;
      }
  
negative.code:   final Map<ClassElement, ClassHierarchyNode> _classHierarchyNodes =
        <ClassElement, ClassHierarchyNode>{};
    final Map<ClassElement, ClassSet> _classSets = <ClassElement, ClassSet>{};
  
    final Set<Element> alreadyPopulated;
  
  