X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/blobdiff_plain/9e91c8e7b5fcdeb6389ac7ccbcd9c77348c4493a..4307347660f48628e307f299eb4fac58ba35fd1a:/src/class-make-impl.lisp

diff --git a/src/class-make-impl.lisp b/src/class-make-impl.lisp
index ed6189f..5b8baf0 100644
--- a/src/class-make-impl.lisp
+++ b/src/class-make-impl.lisp
@@ -243,7 +243,16 @@ (defun check-method-argument-lists (method-type message-type)
   "Signal an error unless METHOD-TYPE and MESSAGE-TYPE have matching argument
    lists.
 
-  This checks that the two types have matching lists of arguments."
+  This checks that (a) the two types have matching lists of mandatory
+  arguments, and (b) that either both or neither types accept keyword
+  arguments."
+  (let ((message-keywords-p (typep message-type 'c-keyword-function-type))
+	(method-keywords-p (typep method-type 'c-keyword-function-type)))
+    (cond (message-keywords-p
+	   (unless method-keywords-p
+	     (error "Method must declare a keyword argument list")))
+	  (method-keywords-p
+	   (error "Method must not declare a keyword argument list"))))
   (unless (argument-lists-compatible-p (c-function-arguments message-type)
 				       (c-function-arguments method-type))
     (error "Method arguments ~A don't match message ~A"