Please see the code at https://run.dlang.io/is/Yjidek
As I understand the error is caused by trying to provide a delegate when there's no context to provide. Not complaining about that.
However what I am complaining about is about the error message: `onlineapp.d(31): Error: delegate onlineapp.S.__lambda2 cannot be struct members`
I'm not sure if it's just me, but that error message makes absolutely no sense to me. Should that message be improved?
