[clang] [-Wunsafe-buffer-usage] Fix assert when constexpr size passed to snprintf() (#119786) (PR #124022)

[Ziqing Luo via cfe-commits]

ziqingluo-90 wrote:

> When possible we should always add tests, I think the right place would be:
> 
> https://github.com/llvm/llvm-project/blob/main/clang/test/SemaCXX/warn-unsafe-buffer-usage-libc-functions.cpp
> 
> CC @ziqingluo-90
> 
> Do we need a release note or is this feature clang-20?

Thanks for reminding us of the test.  
Yeah, this is under `-Wunsafe-buffer-usage-in-libc-call`, which I think needs a release note.

https://github.com/llvm/llvm-project/pull/124022