Linear-base makes writing Linear Haskell easy and fun

Very exciting! The current multiplicity-polymorphic syntax ("a %m -> b") is quite visually jarring; I hope they can work out something nicer. At least the unicode version for the linear arrow ("a ⊸ b") looks good.

Is there anything like a linear state monad? It seems like it would simplify something like Data.Array.Mutable.Linear, where you'd rather not deal explicitly with the "Array a" value returned by every function.