[jkrejcha]

> What I'm emphasizing is that code with safety violations, strictly speaking, isn't C/C++ at all.

This isn't really correct and many programming language standards (including that of C and C++) don't support this view. Many language standards define a notion of conformance. Strictly conforming programs aren't allowed to invoke behaviors that which are undefined[1].

Conforming programs do not have this requirement and basically any non-trivial C and C++ programs are written to this rather than the notion of "strictly conforming".

Most non-trivial programs are not strictly conforming (including some C compilers themselves), generally because restricting the set of targets to something smaller than "any possible C implementation" is useful.

It is perfectly legal (and very desirable in cases where the standards fall short of usefulness) for a C compiler to define undefined behavior. What you compiled is still a C program, just one that isn't portable across the entire potential set of implementations.

[1]: Or unspecified or implementation-defined, for that matter, but this part tends to get left out of discussions.

[tialaramex]

The C++ ISO document describes conforming implementations of their language, ie compilers and similar tools - that conformance isn't a property of your program at all.

So far as I can tell there is no mention of the program conformance you're describing.

[AlotOfReading]

There's a line in the standards that basically says a conforming program is anything acceptable by a conforming implementation. In theory you could have an implementation that gives semantics to UB like Fil-C or CCured do. No mainstream implementation does that for memory unsafety due to the performance overhead, and conforming implementations are required to document those extensions. I don't think there's a sane argument for an implementation to intentionally choose the behavior in the example I provided and Clang certainly doesn't, so it's non-conformant regardless.