Error when trying to make nil or t obsolete

* lisp/emacs-lisp/byte-run.el (make-obsolete, make-obsolete-variable):
Signal error if the symbol to make obsolete is nil or t.  (Bug#62248)
(byte-run--constant-obsolete-warning): New function.
* test/lisp/emacs-lisp/byte-run-tests.el: New file.

1 files changed, 7 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/byte-run.el b/lisp/emacs-lisp/byte-run.el
index a377ec395e1..3e4e4d12cc8 100644
--- a/lisp/emacs-lisp/byte-run.el
+++ b/lisp/emacs-lisp/byte-run.el
@@ -494,6 +494,11 @@ convention was modified."
 Return t if there isn't any."
   (gethash function advertised-signature-table t))
 
+(defun byte-run--constant-obsolete-warning (obsolete-name)
+  (if (memq obsolete-name '(nil t))
+      (error "Can't make `%s' obsolete; did you forget a quote mark?"
+             obsolete-name)))
+
 (defun make-obsolete (obsolete-name current-name when)
   "Make the byte-compiler warn that function OBSOLETE-NAME is obsolete.
 OBSOLETE-NAME should be a function name or macro name (a symbol).
@@ -503,6 +508,7 @@ If CURRENT-NAME is a string, that is the `use instead' message
 \(it should end with a period, and not start with a capital).
 WHEN should be a string indicating when the function
 was first made obsolete, for example a date or a release number."
+  (byte-run--constant-obsolete-warning obsolete-name)
   (put obsolete-name 'byte-obsolete-info
        ;; The second entry used to hold the `byte-compile' handler, but
        ;; is not used any more nowadays.
@@ -539,6 +545,7 @@ WHEN should be a string indicating when the variable
 was first made obsolete, for example a date or a release number.
 ACCESS-TYPE if non-nil should specify the kind of access that will trigger
   obsolescence warnings; it can be either `get' or `set'."
+  (byte-run--constant-obsolete-warning obsolete-name)
   (put obsolete-name 'byte-obsolete-variable
        (purecopy (list current-name access-type when)))
   obsolete-name)