diff --git a/mats/misc.ms b/mats/misc.ms
index bd1132a2e1..ee0dc47c0c 100644
--- a/mats/misc.ms
+++ b/mats/misc.ms
@@ -5303,6 +5303,7 @@
           '(1 2 3))
   (error? ((make-arity-wrapper-procedure (lambda args args) 1 #f) 1 2 3))
   (error? ((make-arity-wrapper-procedure (lambda args args) (expt 2 100) #f) 1 2 3))
+  (equal? (make-list 100 'ok) (apply (make-arity-wrapper-procedure (lambda args args) -1 #f) (make-list 100 'ok)))
 
   (equal? (procedure-arity-mask (make-wrapper-procedure (lambda args args) 1 #f))
           1)
diff --git a/s/cpnanopass.ss b/s/cpnanopass.ss
index b76bbf8f02..c6ef2e6b98 100644
--- a/s/cpnanopass.ss
+++ b/s/cpnanopass.ss
@@ -12882,7 +12882,7 @@
                                     ,(fail)))
                                ;; Arg count is > fixnum width; allow if the fixnum
                                ;; is negative
-                               (if ,(%inline u< ,%ts (immediate 0))
+                               (if ,(%inline < ,%ts (immediate 0))
                                    ,e
                                    ,(fail)))
                            ;; Arity is a bignum...