Segfault connected with taking class-of memoized code?

[Neil Jerram]

Current CVS Guile, trying to investigate why

(with-output-to-string (lambda () (help acons)))

doesn't work...

address@hidden:~$ guile -q
guile> (with-output-to-string (lambda () (help acons)))
<unnamed port>: In procedure length in expression (length exp):
<unnamed port>: Wrong type argument in position 1: (address@hidden acons)
ABORT: (wrong-type-arg)

Type "(backtrace)" to get more information or "(debug)" to enter the debugger.
guile> (debug)
This is the Guile debugger; type "help" for help.
There are 12 frames on the stack.

Frame 11:   [length (address@hidden acons)]
debug> up
Frame 10:   [= ...
debug> up
Frame 9:    [not ...
debug> up
Frame 8:    (cond ((not (= (length exp) 2)) (help-usage)) ((not (feature? 
(quote regex))) (display "`help' depends on the `regex' feature.
You don't seem to have regular expressions installed.
")) (#t (let ((name (cadr exp))) (cond ((symbol? name) (help-doc name 
(string-append "^" (regexp-quote (symbol->string name)) "$"))) ((string? name) 
(help-doc name name)) ((and (list? name) (= (length name) 2) (eq? (car name) 
(quote unquote))) (let ((doc (object-documentation (local-eval (cadr name) 
env)))) (if (not doc) (simple-format #t "No documentation found for ~S
" (cadr name)) (write-line doc)))) (else (help-usage))) *unspecified*)))
debug> evaluate exp
;value: (address@hidden acons)
debug> evaluate (list? exp)
;value: #f
debug> evaluate (class-of exp)
Segmentation fault
address@hidden:~$ 

Regards,
        Neil