anchor.diff:          | _ -> None
   
       let (|Abstract|_|) (m : MethodInfo) = if m.IsAbstract then Some() else None
  -    let (|Virtual|_|) (m : MethodInfo) = if m.IsVirtual then Some() else None
   
   open MethodInfo
   
  
positive.code:         errors.[propertyName] <- messages
          errorsChanged.Trigger(this, DataErrorsChangedEventArgs propertyName)
  
  and internal PropertyInterceptor() =
      let data = Dictionary()
  
      interface IInterceptor with
  
negative.code:                         let returnType = invocation.Method.ReturnType
                          if returnType.IsValueType then 
                              invocation.ReturnValue <- Activator.CreateInstance returnType
                  | _ -> 
                      invocation.Proceed()
  
  