When my master lich levels up and becomes an Arch-lich, will it die if they have been genocided?

Solution 1:

I found out that it does die, unfortunately :(

This is the message produced when it levels up into an Arch-lich:

As the invisible <name> grows up into an arch-lich, he/she expires!

sigh. Should've genocided master mind flayers.

Things I've learned from this/things to note:

This does not result in an alignment penalty (but we all know you did it)
As soon as you see your pet get to the level before that genocided level, you should get it polymorphed (polymorph trap or wand, though I advise against wasting your polymorphing wand on this) so it doesn't "expire".