Question for all my 1031 heroes

[Luka Milicevic]

Let's say I sell a rental property (Single fam) at a profit and decide to do a 1031 to another single fam. Let's say it checks out and it qualifies as a like kind exchange. 

I then decide to live in the house and it ends up qualifying over time as a primary residence for tax purposes. I then sell the house. What happens to the 1031 gains?

Any thoughts you can add would be extremely appreciated.

I'm not in this situation right now, I just thought about it today and I'm curious.