stepper problem with &optional parameters?

[JAN92@uno.cc.geneseo.edu]

Given this as the function declaration parameter list:

(defun binary-search (element-value element list 
                                                  &optional (begin-element 1)
                                                  (end-element (length list))
                                                  (location 0))

... when using the stepper to step through a call to this function this is 
what appears:


(binary-search '3 '3 foo)
  foo = (0 2 4 8 16 ...)
  (ccl::%init&bind begin-element 1)
  nil
  
Error >> Can't take CDR of #<Compiled-function ccl::%local-ref (Non-Global)  #x1CB086>.
(binary-search '3 '3 foo)


The strange thing is, sometimes it happens, sometimes it doesn't.

What's the deal?




John