anchor.diff:      FunctionType subType = _rules.elementType(element);
       // TODO(vsm): Test for generic
       final isGetter = element is PropertyAccessorElement && element.isGetter;
  -    FunctionType baseType = _getBaseMemberType(subType, type, element);
  +    FunctionType baseType = _getMemberType(type, element);
   
       if (baseType != null) {
         //var result = _checkOverride(subType, baseType);
  
positive.code:   }
  
  
    /// Looks up the declaration that matches [element] in [type] and returns it's
    /// declared type.
    FunctionType _getBaseMemberType(FunctionType subType,
        InterfaceType type, ExecutableElement member) {
      ExecutableElement baseMethod;
      String memberName = member.name;
  
  
negative.code: 
      // Check all interfaces reachable from the `implements` clause in the
      // current class against definitions here and in superclasses.
      var localInterfaces = new Set();
      type.interfaces.forEach((i) => find(i, localInterfaces));
      for (var interfaceType in localInterfaces) {
        _checkInterfaceOverrides(type, interfaceType, includeParents: true);
      }
  
  