> Can this feature proposal be lifted from a best-effort base to be
> reproducible?
>
> Something like preconditions contracts, which have to be provably be true
> at compile-time.
>
> Can there be hints to guide the compiler to a deterministic proof?
>

We could at least specify that if the condition is a constant expression,
the assertion behaves correctly instead of being best-effort. Anything past
that would seemingly require us to standardize a bunch of control flow and
data flow analysis, and I don't think anyone wants to do that just for the
sake of this assertion.

I think the target audience for this feature is aware that it's playing
Russian Roulette with compiler errors, and should probably never be used in
large production code bases that compile with more than one compiler, or at
least not with default build flags. Making the feature even slightly more
predictable comes with great effort, and I don't think it would
meaningfully impact who would or wouldn't use the feature.