pragma(__ctfe)

[Bruce Carneal]

On Thursday, 28 September 2023 at 06:04:51 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> On 28/09/2023 6:04 PM, ryuukk_ wrote:
>> Why couldn't the compiler already guess this?
>> 
>> To me a simple static analysis would be enough and better, or 
>> is it too slow? time saved not generating what's not used 
>> could offset time spent on the analysis?
>
> When you do multi-step builds (which are common), this would 
> result in link failures. Since you don't have all the code, you 
> can't do any analysis without failures being possible. It would 
> make druntime and Phobos fail to link correctly with a giant 
> list of missing symbols.

Correct.  If the function is intended to actually be ctfe only, 
as marked, and a reference somehow gets emitted to be linked 
against, then you will see a link time error.