+
+ ;; KLUDGE: SET-ARG-INFO contains the error-detecting logic for
+ ;; detecting attempts to add methods with incongruent lambda
+ ;; lists. However, according to Gerd Moellmann on cmucl-imp,
+ ;; it also depends on the new method already having been added
+ ;; to the generic function. Therefore, we need to remove it
+ ;; again on error:
+ (let ((remove-again-p t))
+ (unwind-protect
+ (progn
+ (set-arg-info generic-function :new-method method)
+ (setq remove-again-p nil))
+ (when remove-again-p
+ (remove-method generic-function method))))
+
+ ;; KLUDGE II: ANSI saith that it is not an error to add a
+ ;; method with invalid qualifiers to a generic function of the
+ ;; wrong kind; it's only an error at generic function
+ ;; invocation time; I dunno what the rationale was, and it
+ ;; sucks. Nevertheless, it's probably a programmer error, so
+ ;; let's warn anyway. -- CSR, 2003-08-20
+ (let ((mc (generic-function-method-combination generic-functioN)))
+ (cond
+ ((eq mc *standard-method-combination*)
+ (when (and qualifiers
+ (or (cdr qualifiers)
+ (not (memq (car qualifiers)
+ '(:around :before :after)))))
+ (warn "~@<Invalid qualifiers for standard method combination ~
+ in method ~S:~2I~_~S.~@:>"
+ method qualifiers)))
+ ((short-method-combination-p mc)
+ (let ((mc-name (method-combination-type mc)))
+ (when (or (null qualifiers)
+ (cdr qualifiers)
+ (and (neq (car qualifiers) :around)
+ (neq (car qualifiers) mc-name)))
+ (warn "~@<Invalid qualifiers for ~S method combination ~
+ in method ~S:~2I~_~S.~@:>"
+ mc-name method qualifiers))))))
+