testlet : Integer -> Integer
testlet $x = let y = prim__add_Integer x x in 
                 prim__add_Integer y y 

data Nat : Type where
     Z : Nat
     S : Nat -> Nat

plus : Nat -> Nat -> Nat
plus Z     $y = y
plus (S $k) $y = S (plus k y)

fn2 : Nat -> Nat -> Nat
fn2 $x $y 
    = let w : Nat
          w = plus x x;
          help : Nat -> Nat
          help $z = plus z w in
          plus (help y) w

fn : Nat -> Nat -> Nat
fn $x $y 
    = let w : ?; w = plus x x in
      let foo = plus x x in
      let help : Nat -> Nat;
          help $z = plus z w in
      plus (help y) foo

localdata : Nat -> Nat
localdata $var =
   let data Bool : Type where
            False : Bool
            True : Bool

       isS : Nat -> Bool
       isS Z = False
       isS (S $k) = True

       boolToNat : Bool -> Nat
       boolToNat False = Z
       boolToNat True = S var in
   boolToNat (isS var)