Un-deprecate oset and oset-default

For discussion see the following threads:
https://lists.gnu.org/archive/html/emacs-devel/2020-05/msg00630.html
https://lists.gnu.org/archive/html/emacs-devel/2020-05/msg00674.html
https://lists.gnu.org/archive/html/emacs-devel/2020-06/msg00099.html

* lisp/emacs-lisp/eieio.el (oset, oset-default): Un-deprecate.
* lisp/emacs-lisp/eieio-core.el (eieio-oref): Declare gv-setter here
instead of in lisp/emacs-lisp/eieio.el.  Suggested by
Stefan Monnier <monnier@iro.umontreal.ca>.
(eieio-oref-default): Add gv-setter declaration.
* etc/NEWS: Announce these changes.
* doc/misc/eieio.texi (Accessing Slots): Document oref and
oref-default as generalized variables.  Consistently document
getters before setters.
* test/lisp/emacs-lisp/eieio-tests/eieio-tests.el: Use
lexical-binding.
(eieio-test-13-init-methods): Simplify.
(eieio-test-33-instance-tracker): Declare IT-list as special.

1 files changed, 6 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index ed4722b27f5..27e511047e6 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -112,7 +112,12 @@ setting the variable 'auto-save-visited-mode' buffer-locally to nil.
 ** New bindings in occur-mode, 'next-error-no-select' bound to 'n' and
 'previous-error-no-select' bound to 'p'.
 
-** EIEIO: 'oset' and 'oset-default' are declared obsolete.
+** EIEIO
+
++++
+*** The macro 'oref-default' can now be used with 'setf'.
+It is now defined as a generalized variable that can be used with
+'setf' to modify the value stored in a given class slot.
 
 ** New minor mode 'cl-font-lock-built-in-mode' for `lisp-mode'.
 The mode provides refined highlighting of built-in functions, types,