@zygoloid: this looks good as is, but there are interesting details here about how the dangling can happen (either because a variable loc is not elided, or because the "trivial type may be copied anyway" rule is used), which sounds interesting enough that we may want to spell it out. Thoughts?

While I agree that the two different ways that the pointer can dangle are (abstractly) interesting, I don't think they're what this example is trying to point out and would probably be more of a distraction than a help here.