exact l.2.2
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l : PosFin n
hc : c.isUnit = some (l, true)
hsize : (f.assignments.modify l.val addPosAssignment).size = n
i : PosFin n
b : Bool
hb :
  hasAssignment b
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
            assignments := f.assignments.modify l.val addPosAssignment }.assignments[i.val] =
    true
hf : hasAssignment b f.assignments[i.val] = true → unit (i, b) ∈ f.toList
i_in_bounds : i.val < f.assignments.size
⊢ l.val < n
no goals