allMembers broke for __

[Adam D. Ruppe]

On Sunday, 17 June 2018 at 01:02:17 UTC, DigitalDesigns wrote:
> If this was a sane language constraint then any identifiers 
> starting with __ that were not reserved would at least give a 
> warning but particularly give an error! Not fail silently and 
> break code in ways that cannot be determined otherwise.

It is undefined behavior to use ANY identifier with __ leading. C 
works exactly the same way.