On Thu, Dec 15, 2022 at 7:37 AM Dr. Arne Babenhauserheide <arne_bab@web.de>
wrote:

> Is this guaranteed or just an implementation detail?

That depends on how you interpret it. IIRC, that all "" are the same object
was done to avoid having tons of "" in pure space. So in that sense, is
guaranteed. And, as such, the warning is superfluous in this specific case.

Anyway, as documented, that identical constant strings are different
objects is, in general, an implementation detail, and the same goes for
floats:

*Emacs Lisp Reference, 2.8 Equality Predicates*

          (eq 3.0 3.0)
               ⇒ t or nil
          ;; Equal floats may or may not be the same object.

          (eq "asdf" "asdf")
               ⇒ t or nil
          ;; Equal string constants or may not be the same object.