When copying unions, we need to only copy the active field of the source union, which we were already doing. However, we also need to zero out the (now) inactive fields, so we don't end up with dangling pointers in those inactive fields.
When copying unions, we need to only copy the active field of the source union, which we were already doing. However, we also need to zero out the (now) inactive fields, so we don't end up with dangling pointers in those inactive fields.