bug#27016: possible bug in `defsetf'

[npostavs]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> A comment in the definition of `gv-define-expander' says:
>
>   ;; Use eval-and-compile so the method can be used in the same file as it
>   ;; is defined.
>   ;; FIXME: Just like byte-compile-macro-environment, we should have something
>   ;; like byte-compile-symbolprop-environment so as to handle these things
>   ;; cleanly without affecting the running Emacs.

I think fixing that would not fix this bug, because the (setf (foobar
pair) 0) would still be compiled according to
byte-compile-symbolprop-environment.  It would just mean that compiling
the file containing (defsetf foobar setcar) would not affect other files
in the compiler's session.