{
const struct val_lab *label;
- if (val_labs_count (a) != val_labs_count (b) || a->width != b->width)
+ if (val_labs_count (a) != val_labs_count (b))
+ return false;
+
+ if (a == NULL || b == NULL)
+ return true;
+
+ if (a->width != b->width)
return false;
HMAP_FOR_EACH (label, struct val_lab, node, &a->labels)