On Sun, 22 Feb 2026, 03:29 Jonathan Grant via Std-Proposals, <
std-proposals_at_[hidden]> wrote:

> Following on from my email thread, I am sharing a draft of my
> compile_assert proposal as a PDF below.
>
>
> https://github.com/jonnygrant/compile_assert/blob/main/proposal/compile_assert__isocpp__PnnnnR0.pdf
>
> Is there anything people would like to see, what would be useful to add?
>
> I've put a call out for small 'tricky' examples I can try below.
>
> I appreciate all the discussion so far.
> I've added detail to my draft to cover some of issues raised. ie relying
> on optimizer, making code backwards compatible so compile_assert completely
> compiles out if the feature is not enabled on a particular compiler.
>
>
>
>
> Abstract
>
> Following the recent mailing list discussion of my 2023 compile_assert()
> proposal, this paper introduces compile_assert(expression, message), a new
> C++ keyword


The proposal is for a macro not a keyword, so this abstract (which isn't
the abstract from the PDF) is misleading.

The proposal talks about adding _Compile_assert but that doesn't seem
necessary or desirable (that's how features are added in C, not in C++).

The proposal doesn't mention that virtually all code using it must be
inline functions or function templates, or have internal linkage, because
if a function that uses the macro is not completely optimized away, it will
refer to the function with the error attribute and that's ill-formed.

The proposal doesn't mention that the error attribute is non-standard. Do
all compilers even support something like that? How would this be
implemented on compilers that don't support that GCC feature?

All the examples are trivial. Can you show it being used in larger
codebases? Even an example with more than one translation unit would be
more interesting than just 16 different main() functions. Most applications
consist of more than main() and one or two static functions in the same
translation unit.




for enforcing assertions at compile time within ordinary (non-constexpr)
> functions.
>
>
> I'm also particularly interested in any feedback from anyone who is using
> compile_assert() to detect issues in all C/C++ software, and in particular
> safety critical systems, automotive, aviation, medical etc.
>
> Also interested if anyone would like to share more simple examples where
> it has been beneficial. Of course if you have any tricky examples, please
> do share them with me, I'll try find a way to get them to be checked by
> compile_assert()
>
> Any feedback about the draft will be really appreciated!
>
> Jonathan
>
>