Found it! Here's what you need to do:
1. Capture a male Numel and evolve it to become Camerupt; when it evolves, it learns Rock Slide.
2. Breed Camerupt with Spheal, since they're both in the Ground egg group.
3. Breed the baby Spheal with Corsola, since they're both in the Water 1 egg group.
4. I believe by then you'd have all the moves on Corsola, assuming you used the Corsola with all the previously required moves, so then you just breed it with Lileep and there you have a Lileep with Rock Slide, Barrier, Mirror Coat, and Recover!
Hope this helps!
All research done on Serebii.net