Timothy Lochner

I feel that correctness as an option it's unfair. Of course we want our code to be correct. What good is beautiful or fast code if it doesn't do anything. More interesting poll is what is important AFTER correctness.

The first of the code virtues is that it works.

Much code appears to work but on closer inspection does not actually.

I'm not sure I understand this. Is it just that the programmer forgot to test corner cases or that the behavior is able to change over time somehow?

Code that contains undefined behavior will appear to work in some situations and fail in others. Example: it may rely on the debugger default initializing values, or it may rely on objects being eliminated by the optimizer, all accidentally.

Example: https://godbolt.org/z/CRYzBI  Only an optimized build on GCC exposes the UB. Only an optimized build on GCC gives you the appropriate warning. All cases are UB. The code appears to work. It's subject to breaking with different versions of different compilers.