Annoying STYLE-WARNING for defmethod &key

[Faré]

When I compile the second of these files after I compiled the first one, I get a STYLE-WARNING: "The function was called with nine arguments, but wants exactly one." at each of the inner calls to check-invariant.

However, if I concatenate these two files into a single one, then I do not get any STYLE-WARNING.

I believe this is a (admittedly minor) bug in SBCL, and there should never be a STYLE-WARNING.

Note: using SBCL 1.0.35.10 on Linux amd64, default features.

;;; interface.lisp

(in-package :cl)

(eval-when (:compile-toplevel :load-toplevel :execute)
  (proclaim
   #+sbcl
   '(optimize
     (sb-c::merge-tail-calls 3)
     (sb-c::insert-debug-catch 0)
     (speed 3) (space 3) (debug 2))))

(defpackage :bug
  (:use :cl))

(in-package :bug)

(defgeneric check-invariant (object &key))

(defmethod check-invariant :around (object &key)
  (call-next-method)
  object)

;;; tree.lisp

(in-package :bug)

(defgeneric node-key (node))

(defclass binary-branch ()
  ((left
    :initarg :left
    :initform nil
    :reader left)
   (right
    :initarg :right
    :initform nil
    :reader right)))

(defmethod check-invariant ((node binary-branch) &key
                            lower (lowerp lower) upper (upperp upper))
  (let ((key (node-key node)))
    (when lowerp
      (assert (< lower key)))
    (when upperp
      (assert (< key upper)))
    (when (left node)
      (check-invariant (left node) :lowerp lowerp :lower lower :upperp t :upper key))
    (when (right node)
      (check-invariant (right node) :lowerp t :lower key :upperp upperp :upper upper))))

[Stas Boukarev (stassats)]

Can't reproduce anymore.