My last fix left n used unitialized in tha a==b case.
Fix, by not using n at all in that case.
Needs to be applied to release23-maint, too.
diff --git a/Objects/listobject.c b/Objects/listobject.c
index ed28200..727c9e6 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -475,7 +475,7 @@
if (a == b) {
/* Special case "a[i:j] = a" -- copy b first */
int ret;
- v = list_slice(b, 0, n);
+ v = list_slice(b, 0, b->ob_size);
if (v == NULL)
return -1;
ret = list_ass_slice(a, ilow, ihigh, v);