Given some expression exp I'd like to differentiate whether that expression results in an xvalue or an prvalue. In order to do so, I'd like to find a context in which evaluating the expression results in a compiler error if it's one of these value types, and compiles fine if it's the other.
Is there such a context that works ideally for fundamental, pod as well as non-pod types?
Alternatively a context which yields different results based on the value type would be sufficient, too.
Background: For an answer of mine I'd like to check whether an expression is an xvalue or not.
