Request for Comment assert(__ctfe)

[Jonathan Marler]

On Sunday, 5 April 2020 at 13:26:22 UTC, Basile B. wrote:
> On Sunday, 5 April 2020 at 12:11:23 UTC, Stefan Koch wrote:
>> Hi Guys,
>>
>> [...]
>>
>> What do you guys think?
>>
>> Cheers,
>>
>> Stefan
>
> I'd prefer a new func attribute `@ctfe`.
> Also I find the current implementation unplesant. Cant you just 
> check the assertion when they are already visited elsewhere e.g 
> in dmd.expressionsem.ExpressionSemanticVisitor.visit(AssertExp) 
> ? Also what if we are in a contract ?

I agree that a function attribute makes more sense for a feature 
like this, however, this solution doesn't solve the general case 
(i.e. elide functions that are only called at compile-time but 
don't have assert(__ctfe) because they are available to be called 
at runtime).  Given that, I believe solving the general case is 
only a matter of implementation rather than a language change.  
So I would hate to add a new language feature that would become 
obselete once the tooling is better.

So I say yes, I'd be fine with this "hack" to temporarily provide 
a path for programs to create CTFE-ONLY functions that won't go 
to code generation.  It's better than the status-quo and can be 
removed if we ever solve the general case.