bug#77374: eval causes temporary modules to leak memory

You can call make-module (from boot-9.scm) as much as you want to create empty modules.
Memory won't leak.

As soon as you call eval with that module, it seems it can't be garbage collected anymore.

This bug also appears as part of the (@ (rnrs eval) environment) procedure because it uses both of those.

Try it out:
(format #t "kb: ~a\n" (floor (/ (assoc-ref (gc-stats) 'heap-size) 1024)))
(let lp ((x 0))
   (unless (eqv? x 50000)
     (let ((m (make-module)))
       (eval '1 m) ;; comment this line to remove memory leak
       2)
     (lp (1+ x))))
(gc)
(format #t "kb: ~a\n" (floor (/ (assoc-ref (gc-stats) 'heap-size) 1024)))