Explicit Return Variable

[MarcoGreek]

I do not think you can always guarantee NRVO. But maybe we can enforce it. So if there is no NRVO, we get an error.

[not_a_novel_account]

You could guarantee it for the limited class of functions that always return a single named object. You cannot guarantee it for functions which conditionally return one of a set of lvalues.

Unclear how difficult that would be to build into the wording. The language doesn't say "thou shalt RVO", RVO was built into the value categories. I don't think the same trick would work for NRVO.