Should not compare `undef` (deleted) key in hashes; fix
MODIFY
src/hash.c
src/hash.c
@@ -402,7 +402,8 @@ sg_index_get(mrb_state *mrb, seglist *t, mrb_value key, mrb_value *vp)
size_t step = 0;
while (index->table[k]) {
- if (sg_hash_equal(mrb, t, key, index->table[k]->key)) {
+ mrb_value key2 = index->table[k]->key;
+ if (!mrb_undef_p(key2) && sg_hash_equal(mrb, t, key, key2)) {
if (vp) *vp = index->table[k]->val;
return TRUE;
}

Should not compare `undef` (deleted) key in hashes; fix #4136