*
* Note that if NULL is passed for dbg_info_merge_pair or dbg_info_merge_sets, the default
* implementations default_dbg_info_merge_pair() and default_dbg_info_merge_sets() are used.
*
* Note that if NULL is passed for dbg_info_merge_pair or dbg_info_merge_sets, the default
* implementations default_dbg_info_merge_pair() and default_dbg_info_merge_sets() are used.