Infinite continuation loop corrupts stack(?)

[Moritz Heidkamp]

This program:

(let ((loop #f))
  (call/cc (lambda (f)
             (set! loop f)))
  (print 123)
  (loop))

prints lines of "123" for a while until it aborts with this error:

[panic] Detected corrupted data in stack - execution terminated

[Moritz Heidkamp]

Just found out that adding an explicit (gc) to the loop fixes the problem. So apparently the GC doesn't realize that it needs to do its job here :-)

[sjamaan]

In CHICKEN 4, we get an error that loop is invoked without any arguments. If I change the call so it's (loop loop), it does not error in C5.

This could point to a problem with the number of arguments the continuation is invoked versus how it is expected to be invoked. Strictly speaking, it shouldn't care about the number of arguments (given that it doesn't do anything with the value(s) returned by the call/cc call).

[sjamaan]

Perhaps 2dc0c5929abc398f1d344500fba9fc10ed4857cc is the culprit?

[sjamaan]

I've also noticed that (receive (x) (call/cc (lambda (f) 1 (values))) (print x)) does not error out; it prints #<unspecified>, which is definitely wrong.

[sjamaan]

That expands to (##core#let ((x (call/cc (lambda (f) (values))))) (print x)) and this doesn't work. An explicit call to call-with-values works.

[sjamaan]

Simplified, this gives unspecified too: (let ((x (values))) (print x))

[sjamaan]

And also (print (values))

[sjamaan]

This was the same in CHICKEN 4 though!

[sjamaan]

Fixed with 3e0f640ecf22f6be7af1947b875132415556ca5b (not signed-off, but discussed at SaarCHICKEN)