Comment by nayuki

Thanks for the investigation. Oops, it seems like MSan (memory sanitizer) is the appropriate tool that detects uninitialized reads? https://stackoverflow.com/questions/68576464/clang-sanitizer...

I only use UBSan and ASan on my own programs because I tend not to make mistakes about initialization. So my knowledge is incomplete with respect to auditing other people's code, which can have different classes of errors than mine.

Thank goodness that every language that is newer than C and C++ doesn't repeat these design mistakes, and doesn't require these awkward sanitizer tools that are introduced decades after the fact.