BetterC and CTFE mismatch

[Nicholas Wilson]

On Wednesday, 26 September 2018 at 12:51:57 UTC, Steven 
Schveighoffer wrote:
>> So anything I do at CTFE has to be betterC as well? That is a 
>> bummer.
>
> This is an artificial, and not really intended, limitation. 
> Essentially, CTFE has to be a real function. If it's defined, 
> it's expected to be callable from runtime as well as CTFE.
>
> But I can't see why, if you don't call from runtime, it should 
> matter. I think this has to do with the places betterC is 
> enforced in the compiler.
>
>> 
>> I'll try to workaround this, but I would like to see this 
>> fixed. Is there anything I can do to move this forward?
>
> I'd suggest a bug report if one hasn't been made.
>
> -Steve

https://issues.dlang.org/show_bug.cgi?id=18472 is an open 
regression on 2.078. Doesn't cover all use cases of what 
Sebastiaan might want though.