simp only [List.foldl, imp_self]
case nil
n : Nat
assignments0 : Array Assignment
assignments0_size : assignments0.size = n
rupUnits : Array (Literal (PosFin n))
assignments : Array Assignment
assignments_size : assignments.size = n
b : Bool
⊢ insertUnit_invariant assignments0 assignments0_size rupUnits assignments assignments_size →
    let update_res := List.foldl insertUnit (rupUnits, assignments, b) [];
    let_fun update_res_size := ⋯;
    insertUnit_invariant assignments0 assignments0_size update_res.fst update_res.snd.fst update_res_size
no goals