What should happen when the assert message expression throws?

[kdevel]

On Friday, 25 November 2022 at 12:29:26 UTC, Ali Çehreli wrote:

> According to common assert wisdom, the program must not 
> continue once an assertion has failed because the program is in 
> invalid state.

Whatever "invalid state" means. I could not find a definition in 
the manual. Usually a system is said to be in some state s of a 
set of possible states S. Now one can devise a proper subset I ⊊ 
S and say "the system is in an invalid state" iff s ∈ I. That is 
a precise definition but is still meaningless.

> However, the main thread of a D program does execute code to 
> display the backtrace to help the programmer discover why the 
> assertion failed. By the wisdom above, this is best-effort 
> because if the program is in an invalid state, the code that 
> attempts to display the backtrace can e.g. delete files.

Pardon! What?

> I had discovered that fact when I first started catching Errors 
> in non-main threads to do exactly what the main thread does. I 
> used to feel guilty about that but now I know it's all 
> best-effort anyway: it may or may not work.
>
> Add to the above another observation which I had after Patrick 
> Schluter's message: Even the execution of the assert check is 
> best-effort because if the check will fail, the program has 
> been in invalid state for an unknow amount of time anyway.

int main ()
{
    int a = 1;
    try
       assert (a == 0);
    catch (Throwable t)
       {}
    return 0;
}

Which line makes the program enter the "invalid state"? 
Additional question: What constitutes that "invalid state"?