Filter for opDispatch?

[frame]

On Saturday, 15 May 2021 at 23:59:49 UTC, Paul Backus wrote:
> On Saturday, 15 May 2021 at 23:41:19 UTC, frame wrote:
>> On Friday, 14 May 2021 at 23:02:22 UTC, frame wrote:
>>
>>> Thanks! I stumbled around with static asserts and mixins... 
>>> totally forgot about the constraints but they will to the 
>>> trick.
>>
>> Now I run into the error
>>
>> "class Foo member s is not accessible"
>> "template instance Base.opDispatch!("s", int, Foo) error 
>> instantiating"
>>
>> and I have no clue why.
>
> Does it work if you remove `protected` from the derived class?

Yes, but why should the derived class not have access to it?