On 2013-04-30, at 8:36 PM, Jason Felice <jason.m.felice@gmail.com> wrote:

I haven't been able to separate the code from my repo and make it still break, but I found what I imagine is an inlining bug when --enable-auto-force is enabled.

My repo: https://github.com/maitria/scheme-stuff.git

$ make $ gsi

...

(load "scheme-stuff.o1") (for-each pp (delay (cons 1 (delay (cons 2 '()))))) 1 2>

Change lib/iteration.scm:14 and replace end-position? with null? and repeat:

...

(for-each pp (delay (cons 1 (delay (cons 2 '()))))) *** ERROR IN iteration#for-each -- (Argument 1) PAIR expected (car '()) 1>

The definition of end-position? is:

(define end-position? null?)

Adding an extraneous force call -- (loop (force (cdr position))) -- will prevent the problem.

Indeed the expansion of your example shows the problem : % gsc -c -expansion example.scm Expansion: (define for-each (lambda (proc iterable) (letrec ((loop (lambda (proc position) (if (if ('#<procedure #2 ##eq?> null? '#<procedure #3 null?>) ('#<procedure #4 ##null?> position) (null? position)) #!void (let ((begin-temp.0 (proc (if (and ('#<procedure #2 ##eq?> car '#<procedure #5 car>) ('#<procedure #6 ##pair?> position)) ('#<procedure #7 ##car> position) (car position))))) (loop proc (if (and ('#<procedure #2 ##eq?> cdr '#<procedure #8 cdr>) ('#<procedure #6 ##pair?> position)) ('#<procedure #9 ##cdr> position) (cdr position)))))))) (loop proc (first-position iterable))))) The problem is the speculative inlining of the null? primitive which calls ##null?, the primitive which tests for an empty list *without* forcing its argument. That needs to be fixed. The workaround is to disable the inlining of primitives with the declaration : (declare (not inline-primitives)) . Marc