> Even if not mandated by the standard, concrete standard library implementations do provide bound checking on span (and vector, and optional, etc.), but, even when meant for production use, are disabled by default.
That's a choice though. You can enable these in your production builds if you want (with libstdc++ at least) and some Linux distributions have chosen to do just that.
The thing though is that these checks are NOT free and the overhead is not justified for all use cases so forcing them on everyone is not appropriate for C++.
> The thing though is that these checks are NOT free and the overhead is not justified for all use cases so forcing them on everyone is not appropriate for C++.
Well, that's why they should be a flag. The question is whether it should be enabled by default or not.
That's a choice though. You can enable these in your production builds if you want (with libstdc++ at least) and some Linux distributions have chosen to do just that.
The thing though is that these checks are NOT free and the overhead is not justified for all use cases so forcing them on everyone is not appropriate for C++.