Fix eieio vs cl-generic incompatibilities found in Rudel (bug#23947)

* lisp/emacs-lisp/cl-generic.el (cl-generic-apply): New function.
* lisp/emacs-lisp/eieio-compat.el (eieio--defmethod): Fix incorrect
mapping between cl-no-applicable-method and EIEIO's no-applicable-method.
* lisp/emacs-lisp/eieio-core.el (eieio--class-precedence-c3):
`class' is not a symbol but a class object.

1 files changed, 9 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/cl-generic.el b/lisp/emacs-lisp/cl-generic.el
index e5bab8dba99..4f263c6bb8d 100644
--- a/lisp/emacs-lisp/cl-generic.el
+++ b/lisp/emacs-lisp/cl-generic.el
@@ -671,6 +671,15 @@ FUN is the function that should be called when METHOD calls
           (setq fun (cl-generic-call-method generic method fun)))
         fun)))))
 
+(defun cl-generic-apply (generic args)
+  "Like `apply' but takes a cl-generic object rather than a function."
+  ;; Handy in cl-no-applicable-method, for example.
+  ;; In Common Lisp, generic-function objects are funcallable.  Ideally
+  ;; we'd want the same in Elisp, but it would either require using a very
+  ;; different (and less efficient) representation of cl--generic objects,
+  ;; or non-trivial changes in the general infrastructure (compiler and such).
+  (apply (cl--generic-name generic) args))
+
 (defun cl--generic-arg-specializer (method dispatch-arg)
   (or (if (integerp dispatch-arg)
           (nth dispatch-arg