Corpses are considered objects, and the Mending cantrip can do the following:
This spell repairs a single break or tear in an object you touch, such as a broken chain link, two halves of a broken key, a torn cloak, or a leaking wineskin. As long as the break or tear is no larger than 1 foot in any dimension, you mend it, leaving no trace of the former damage.
This spell can physically repair a magic item or construct, but the spell can’t restore magic to such an object.
Could you, therefore, use the Mending cantrip on your dead party member who had his body parts chopped off, to reattach those body parts?
The benefit of doing so would be to be able to use a spell such as Revivify, instead of having to resort to higher level spells like Resurrection or a Regenerate + Revivify combo.