-- let hoisting

\(a : Int) \(b : Int)
let x : Int :=
   let y : Int := b + a in
   let z : Int := b + a in
   b + a + y + z
in
let x2 : Int :=
   let y2 : Int := b + a + x in
   let z2 : Int := b + a in
   b + a + y2 + z2
in
x + a + b + x2