[developers] [spr31181] closure change in ACL 8.0 (from 6.2)?

[David Margolies]

  i attach two files: `test.lisp' and `test.log', of which the latter is
  dribble-bug() output from compiling, loading, and running the piece of
  code that used to work and no longer does in ACL 8.0.

  (in-package :cl-user)

  (eval-when (:load-toplevel :compile-toplevel :execute)
    (let ((n -1))
      (defun reset-failure-count () 
	(setf n -1))

      (defstruct failure
	(id (incf n))
	nature type1 type2 glb path suffix context)))

  (defun test ()
    (make-failure))

Okay, I have reproduced the behavior in 8.0 (and the success in 7.0).
I cannot see any specific change in the relevant code, but it had
vaious minor modifications. (That is, nothing is notated as 'fixing
eval-when problem ...'  Presumably something changed the behavior,
hoever, but that may have been a side effect of some other change.)

As to what should happen, well, I have asked our expert in that for an
opinion and I will tell you what he says.

As a practical matter, this works:

(in-package :cl-user)

(eval-when (:load-toplevel)
  (let ((n -1))
    (defun reset-failure-count () 
      (setf n -1))
    

    (defstruct failure
      (id (incf n))
      nature type1 type2 glb path suffix context)))

(defun test ()
  (make-failure))

while adding :compile-top-level and/or :execute causes failure.  Not
sure why yet, but perhaps that is a useful observation.

David Margolies
Franz Inc.