What should happen when the assert message expression throws?

[Dukc]

On Friday, 18 November 2022 at 12:36:14 UTC, RazvanN wrote:
> What do you think? Is deprecating having an assert message that 
> may throw a severe restriction? Are there other rewrites that I 
> am missing?

In my opinion the fix is clear. When the assertion handler at 
DRuntime determines the assertion has failed, it should call the 
error message generator (it is lazy IIRC) in a try/catch block. 
If the generator throws an exception, the error message of 
assertion failure should be something like `<FormatException 
thrown while writing error message>`.

Should the error generation exception be the `.next` member of 
`AssertError`? Probably, but I'm not sure.

If the message generator throws an unrecoverable error, that 
should probably still mask the assert error. If a `RangeError` 
masks `AssertError` it's unlikely to be a problem since neither 
is likely to be caught and at least in my mind they're 
essentially the same - a "bug detected" error.