On Thu, 29 Apr 2021 at 11:41, Gašper Ažman <gasper.azman@gmail.com> wrote:

As others have said - exceptions are definitely not for situations where you are signaling a bug. That's what contracts are for. Never mind we don't have them, but exceptions are definitely not for signaling bugs. std::logic_error should be deprecated and removed once contracts land (yes, I know it's not gonna happen, but one can dream).

From the contract violation handler, you will definitely be able to both gracefully exit (save the document and terminate, for instance), as well as get the current stack trace.

Exceptions don't give you anything that makes dealing with bugs easier. In other words, exceptions *are* for control flow - exceptional control flow. Not bugs.

I agree, that's great if we manage to get to a place where (a) exceptions are suitable for control flow, and (b) contracts are available to signal bugs. But currently the situation in C++ is that exceptions are expensive to use, so they are unsuitable for control flow, but they can be and are used to signal bugs. Even if both contracts and P0709-style exceptions land in C++23, there will be 25 years' worth of code written in what was at the time Standard C++ that uses exceptions to signal bugs. The facility proposed here would be invaluable dealing with such code.