structs: bugfix in static-slot-ensure.

* struct.c (static_sot_ens_rec): This change is in the case
when a static slot is being ensured in a struct type which
already has that static slot by inheritance. In that
situation, the inheritance is severed and the struct gets its
own non-inherited slot of that name. Then all of the derived
structs are scanned. If any contain the original inherited
slot, it is updated to the new, non-inherited one. The bug
here is that we were copying the home_offs field of the
original inherited slot to the new one! This is wrong; the new
slot is not related to the original inherited one. The new
slot is a home slot and its own offset must be home_offs.
We can calculate that simply as its delta from the static slot
table base.

1 files changed, 1 insertions, 1 deletions

diff --git a/struct.c b/struct.c
index 3b16da7c..6d72d2ae 100644
--- a/struct.c
+++ b/struct.c
@@ -1081,7 +1081,7 @@ static val static_slot_ens_rec(val stype, val sym, val newval,
     to.store = nil;
     to.home_type = stype;
     to.home = &stsl->store;
-    to.home_offs = stsl->home_offs;
+    to.home_offs = stsl - st->stslot;
     static_slot_rewrite_rec(st, stsl, &to);
     set(stslot_loc(stsl), newval);
     return newval;