http://eel.is/c++draft/intro.execution#def:full-expression:

A full-expression is
— an invocation of a destructor generated at the end of the lifetime of an object other than a temporary object ([class.temporary]), or

Here is an example

void foo() { const auto& rk = Klass{}; Klass k; // ... // generated invocation `k.~Klass()` is a full-expression // generated invocation `rk.~Klass()` is not a full-expression? }

I think it is intended to be a full-expression, so the Standard should say something like

other than a temporary object whose lifetime was not extended