Is it permissible to combine the intention of a supererogatory prayer (two rak'ahs for ablution) and a Sunnah prayer (the post-Maghrib Sunnah) in two rak'ahs?

The overlap of acts of worship is divided into two categories:

First: What is permissible for overlap, and its criterion is that one of the two acts of worship is not intended for itself, such as the two rak'ahs for greeting the mosque or the two rak'ahs for ablution. In this case, these two intentions may be fulfilled by a single act.

Second: What is not permissible for overlap, and its criterion is that both acts of worship are intended for themselves, such as the Sunnah of Fajr and the Duha prayer. In this case, neither suffices for the other, and they cannot be combined in a single act.