iter-reset: gc problem.

* lib.c (iter_reset): When we reinitialize the iterator, it can allocate
a new secondary object, e.g. using hash_begin, which is stored into the
iterator. This is potentially a wrong-way assignment in terms of GC
generations and so we must call mut(iter) to indicate that the object
has been suspiciously mutated. We only do this if the iterator has a
mark function. If it doesn't have one, then it isn't wrapping a heap
object, and so doesn't have this issue.
(seq_reset): This has the same issue, and the fix is the same. Since ths
function is obsolescent, we don't bother doing the si->ops->mark check;
we optimize for code size instead.

1 files changed, 3 insertions, 0 deletions

diff --git a/lib.c b/lib.c
index 15909c6c..dca7474d 100644
--- a/lib.c
+++ b/lib.c
@@ -1183,6 +1183,7 @@ val seq_reset(val iter, val obj)
   struct seq_iter *si = coerce(struct seq_iter *,
                                cobj_handle(self, iter, seq_iter_cls));
   seq_iter_init(self, si, obj);
+  mut(iter);
   return iter;
 }
 
@@ -1350,6 +1351,8 @@ val iter_reset(val iter, val obj)
     {
       struct seq_iter *si = coerce(struct seq_iter *, iter->co.handle);
       seq_iter_init_with_info(self, si, sinf, 0);
+      if (si->ops->mark)
+        mut(iter);
       return iter;
     }
     /* fallthrough */