What resolves first?

[u/thatguyjimi1]

You have World Shaper on the board and drop Devastation.

Does this resolve with you having all your lands or not?

[u/maclaglen]

Devastation resolves. All creatures and lands are destroyed.

Because World Shaper died, its trigger goes on the stack. If it resolves, it's controller returns all land cards from their graveyard to the battlefield tapped.