split <;> simp only
n : Nat
f : DefaultFormula n
c : DefaultClause n
⊢ (match c.isUnit with
      | none =>
        { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
          assignments := f.assignments }
      | some (l, true) =>
        { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
          assignments := f.assignments.modify l.val addPosAssignment }
      | some (l, false) =>
        { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
          assignments := f.assignments.modify l.val addNegAssignment }).rupUnits =
    f.rupUnits
no goals