[swift-evolution] [Pitch] #warning

[Chris Lattner]

> On May 29, 2016, at 10:36 PM, Charlie Monroe <charlie at charliemonroe.net> wrote:
> 
>> As to #warning, Swift’s use of warnings are significant different than the use in C.  In C compilers, many of the warnings produced *should* be errors, but can’t be because that effects language conformance and could break a large body of code. 
> 
> The example I've mentioned with #error, doesn't necessarily lead to an error, but can just issue a #warning("Untested OS, proceed carefully.") - it IMHO doesn't necessarily be fatal.

This doesn’t make sense to me.  If the code is untested, then it should definitely be audited and check if it is enabled.  A #error is the perfect approach for this case.

-Chris